WASHINGTON (REUTERS) - The number of terrorist attacks worldwide and deaths from such attacks dropped in 2016 for the second straight year, driven by decreases in Afghanistan, Syria, Nigeria, Pakistan and Yemen, the US State Department said.

The total number of terrorist attacks in 2016 dropped 9 per cent compared with 2015, while fatalities caused by the attacks fell 13 per cent, the department said on Wednesday (July 19) in a report on global terrorism.

The Sunni militant group Islamic State in Iraq and Syria (ISIS) was the deadliest terrorist group last year, carrying out 20 per cent more attacks in Iraq and causing 69 per cent more deaths there compared with 2015.

Data compiled by the University of Maryland for the State Department showed there were a total of 11,072 terrorist attacks worldwide last year, resulting in more than 25,600 deaths. Of those deaths, 6,700 were of perpetrators of the attacks.

Terrorist attacks took place in 104 countries in 2016, but the majority occurred in just five countries: Iraq, Afghanistan, India, Pakistan and the Philippines.

Three-quarters of all deaths from terrorist attacks took place in Iraq, Afghanistan, Syria, Nigeria and Pakistan.

The report spoke positively of recent efforts by Sudan, which was placed on the list of US-designated state sponsors of terrorism in 1993 because of its support of Palestinian and Lebanese militant groups.

"Notwithstanding this history, countering terrorism is today a national security priority for Sudan, and Sudan is a cooperative partner of the United States on counterterrorism,"the report said.

Other US-listed state sponsors of terrorism are Iran and Syria.

Former US President Barack Obama temporarily lifted sanctions on Sudan in January for six months, suspending a trade embargo, unfreezing assets and removing financial sanctions. President Donald Trump's administration last week postponed for three months a decision on whether to permanently lift the sanctions.

State Department spokesman Heather Nauert told reporters in June that no matter what decision is made on the Sudan sanctions, the designation of Sudan as a state sponsor of terrorism will remain in place.

A June filing with the Justice Department showed that Sudan had hired law firm Squire Patton Boggs LLP at a monthly fee of US$40,000 (S$54,700) to represent Sudan's interests in Washington, including avoiding a "snap back" of US sanctions.