WASHINGTON (NYTIMES) - When President Donald Trump announced the latest and most far-reaching version of his travel ban on Sunday (Sept 24), the White House said it had come after exhaustive planning.

It was meant to prevent the confusion and chaos his first travel ban created at airports, colleges and technology companies in America and refugee camps around the world in January.

The White House said the new policy was more narrowly targeted than its precursor, which was swiftly blocked by the courts. But immigrant and diaspora communities from the affected countries once again reacted with dismay, and refugee advocates denounced the new decree as more of the same.

"This is still a Muslim ban," Becca Heller, director of the International Refugee Assistance Project, said in a statement, adding that the changes in the new ban were not material enough to change that.

The first travel ban was blocked by federal judges because it was perceived to discriminate against Muslims; the Trump administration argued it was a security measure designed to thwart terrorism. A revised version of that ban expired on Sunday.

The new version, which is to take effect on Oct 18, adds Chad, North Korea and Venezuela to the list of affected countries and drops Sudan. The other affected countries are Iran, Libya, Syria, Yemen and Somalia.

Different restrictions were imposed on each of the three additions, depending on the threat they were deemed to pose. For example, for Venezuela, the ban applies only to visits by certain government officials and their families, while Somalis are barred from emigrating to the US but not from visiting.

The addition of Chad to Trump's travel ban took the Chadian government by surprise and bewildered analysts of Central Africa.

With a mixed population of Muslims and Christians, Chad has been a longtime US ally in fighting Islamist militants in the region, including offshoots of Al-Qaeda and Boko Haram, and its troops took part in a French-led effort to root out Islamist militants from parts of Mali in 2013.

In a statement, the government expressed "its incomprehension in the face of the official reasons for this decision, which contrasts with Chad's constant efforts and commitments in the fight against terrorism."

It called on Trump to rethink the decision, "which has seriously affected the image of Chad and the good relations maintained by the two countries." The government said it does not want to have to resort to a similar ban on Americans travelling to Chad, "which would be prejudicial to the interests of both countries," and that it was "open to any discussions likely to strengthen its collaboration with the United States of America on security and counterterrorism issues."

In a report on Chad last year, the State Department said few Chadians join terrorist groups, and the country had tightened its borders to impede the movements of militants, but a financial crisis kept the country from consistently paying police and military salaries, which presented some risk.

Matthew Page, who was the State Department's expert in the region until last year, said the travel ban for Chad seemed to be "a knee-jerk move, rather than a carefully considered decision."

Experts said there were many steps Chad could take in response that would have a negative impact on the US, including reducing security protection for employees of the large US embassy. Also at stake are oil exploration plans from companies like Exxon Mobil.

"This is a very draconian move that could put Americans in harm's way," Page said. "There is no incentive to labeling Chadians soft on terrorism, which they definitely are not." Human rights activists also expressed outrage.

"This makes no sense at all, even from a Trumpian standpoint," said Reed Brody, a lawyer for Human Rights Watch who has worked extensively in Chad.

Victims of a former Chadian president, Hissène Habré, who is accused of torturing and murdering opponents during his rule in the 1980s, regularly travel to the US to collect humanitarian awards.

"Think of all the courageous and dedicated activists who will now be barred from the US," Brody said.

Somali-Americans in the Cedar-Riverside area of Minneapolis processed the news of the travel ban as they went about their business in the rain on Monday, voicing wariness of an administration that has frightened them from the start and trying to learn more about the details of the ban.

Slma Osman, 29, said she had just put her three toddlers to bed on Sunday evening when she heard about the travel ban on television, and the news made her cry.

She emigrated from Somalia a year ago to join her husband, and the new ban seemed to scotch her dream of bringing her parents over to unite with her children.

"I feel lonely," she said, walking to a bus stop on her way to work. "When my children grow up, they will feel the pain."

Jamal Hassen, 23, a student in the Twin Cities who was born in Ethiopia to a Somali mother, said he worried about her. "Our moms are going to the mall by themselves, and get harassed because of their headscarves - especially after he got elected," Hassen said. "It was calm before that."

Hassen did not dispute Trump's claim that Somalia's immigration officials do not adequately vet extremists. Some Somali-Americans from the Twin Cities have been recruited by Islamic extremist groups abroad, but Hassen said it was unfair that all Somalis must pay the price. "We are getting punished for what they did," he said.

Kamaal Yusuf, 32, a taxi driver born in Somalia who emigrated as a teenager, heard about the travel ban in a coffee shop after driving his sons to day care. "I feel very sad," he said. "America is supposed to welcome immigrants from all over the world. That's the good I see in America. Now it's messed up."

The Somali minister of information, Abdirahman O. Osman, said in a statement that Somalia was grateful for US assistance and support in reducing the threat posed by terrorists, and that U.S. policy should focus on the terrorists, not on ordinary Somalis.

"Somalis in the U.S. are making valuable contributions to the U.S. society, which is why our young people are hoping to visit one day to the U.S.," Osman said. "Somalis are a peace-loving people, and it is terrorists who are damaging our good names."

It was not immediately clear what led to a special carve-out that permits Iranian students, but not most other Iranians, to continue to obtain visas to travel to the U.S.

Iran sends more students to America than the other countries affected by the ban - 12,269 of them in the 2015-16 academic year, according to the Institute of International Education - and many are graduate students in scientific fields who also serve as teaching assistants.

Pedram Gharghabi, 31, a doctoral candidate and research assistant in electrical engineering at Mississippi State University, said Monday that the implications of the ban were not yet clear but would probably lead to hardships even for exempted students.

"My understanding is that our families will not be allowed to enter the United States for a visit," Gharghabi said.

Because many Iranian students' visas are single-entry and do not permit the students to leave and come back, he said, "that means we may not meet our families for years."

Amin Khalili, 22, who is studying for a master's degree in biomedical engineering at Rutgers University in New Brunswick, New Jersey, learnt of the new rules from a fellow student late Sunday night.

"I think everyone here is in stress and uncertainty," said Khalili, who is from Tehran. "Honestly, a lot of us stopped watching TV. It's been very stressful for all of us."

The new ban appears to keep out all students from Somalia, Syria and North Korea. But it appears to permit those from Chad, Libya, Venezuela and Yemen to travel to the United States to study.

For citizens in some conflict zones, news of the latest travel ban was met with weary shrugs.

"How many times are we meant to condemn this man?" Mohamed Al Amad, a Yemeni journalist in Sanaa, said of Trump. "Most Yemenis are too busy feeling bad about the American bombs that Saudi Arabia is dropping on them to think about Trump's silly ban."

In the Libyan city of Misrata, Ali Busitta, a municipal official, said "the travel ban is wrong and it is offensive," and added, "We understand that the terrorism in Libya looks scary, but you can't just say that we are all bad."

Most Libyans are occupied with the more pressing and often violent problems confronting their country, Busitta said. "Frankly, they are too distracted by what's going on to care about this ban or that ban."

Immigrant advocates scrambled on Monday to address questions from their communities in New York about the latest iteration of the travel ban.

Rama Issa-Ibrahim, executive director of the Arab American Association of New York, said many people who have been petitioning to bring relatives to the United States are confused and anxious now.

"We don't really know how this is going to unfold until Oct 18, but since January, we've seen the chaos that these travel bans, the executive order, has brought to our community and to the country in general," she said. "I suspect this is not going to be an easy ride yet again."

Yemeni-Americans in Brooklyn have been mobilising since the executive order announcing the first travel ban was issued in January. But Rabyaah Althaibani, an activist who was involved in a Yemeni bodega strike across the city in February that was a protest of the original ban, said she felt worn down by yet another one.

"I feel so helpless and fatigued," she said Monday.

Althaibani, 39, has not been able to bring in her Yemeni husband, Basheer Othman, who was a prominent liberal journalist in Yemen. The couple married in January 2016 in India, but they have been apart ever since, with Othman waiting in Malaysia to receive a visa.

"I don't know what it means for him, and it's really scary," Althaibani said through tears on Monday after speaking with him via Skype.

"I'm in limbo, and it's a hellish nightmare."