MOSCOW (AFP) - Fugitive US intelligence leaker Edward Snowden on Friday told activists he wanted to claim asylum in Russia until he can travel on to Latin America, in his first encounter with the outside world since becoming marooned at a Moscow airport three weeks ago.

The dramatic meeting at Sheremetyevo airport with rights groups and lawyers appeared an attempt by Mr Snowden to find a way out of an increasingly difficult situation as he seeks to escape US espionage charges for leaking sensational details of widespread American surveillance activities.

Mr Snowden, 30, told a group of activists and lawyers from organisations such as Amnesty International and Human Rights Watch that he had "no regrets" about his revelations.

"That moral decision to tell the public about spying that affects all of us has been costly, but it was the right thing to do and I have no regrets," Snowden said in a transcript released by the anti-secrecy website WikiLeaks.

Photographs posted on social media by participants showed Snowden dressed in a grey shirt and looking relaxed as he addressed the meeting. He was accompanied by Sarah Harrison, a British WikiLeaks employee who has been with him throughout his stay in Russia.

Mr Snowden, who has no official travel documents, said he needed asylum in Russia before he could work out a way to travel legally to Latin America.

"I will be submitting my request to Russia today (Friday), and hope it will be accepted favourably," he said.

Venezuela, Bolivia and Nicaragua have all indicated they would be open to offering Snowden a safe haven.

"Some governments in Western European and North American states have demonstrated a willingness to act outside the law... This unlawful threat makes it impossible for me to travel to Latin America," Mr Snowden said.

Bolivian President Evo Morales's plane, flying home from a trip to Moscow, was diverted last week after several European nations closed their airspace to him over groundless rumours that Mr Snowden was on board the jet.

Mr Snowden initially applied for asylum in 21 countries, most of which rejected the request, and then made applications to another six nations.

Moscow said last week that Mr Snowden had withdrawn his application for asylum in Russia after President Vladimir Putin said it was conditional on not damaging US interests.

But the participants at the meeting said Mr Snowden had now vowed not to harm the United States, although it was not clear if this meant he was prepared to agree to halt leaking new information about US surveillance activities.

Mr Snowden "promised that he would not act to harm the United States", said lawyer Genri Reznik after attending the meeting.

"He (Snowden) views the Russian president's position with understanding," said Mr Reznik. "He understands that giving him political asylum will complicate ties between Russia and the US." The Kremlin responded Snowden could stay in the country but repeated its condition.

"Mr Snowden could hypothetically stay in Russia if he: first, completely stops the activities harming our American partners and US-Russian relations and second, if he asks for this himself," Mr Putin's spokesman Dmitry Peskov said in comments quoted by Russian news agencies.

In a possible indication that Moscow is now more favourably disposed to Mr Snowden, the powerful speaker of the Russian lower house of Parliament, Sergei Naryshkin, told state television that Russia should grant Snowden asylum, describing him as a "defender of human rights".

Russian ruling party lawmaker Vyacheslav Nikonov who was present at the meeting said Mr Snowden "was a bit jittery" but exuded confidence and a belief he "felt he was right".

"He was not making any jokes because he realises full well the seriousness of his situation," Mr Nikonov said.

Mr Snowden has made no public appearances since arriving at the state-controlled airport in the Russian capital on June 23.

According to officials, he has spent the whole time in the airport transit zone but there has not been a single verifiable sighting of him until now.

The US embassy in Moscow used Friday's meeting to relay a message to Mr Snowden warning him he should face justice at home, according to Human Rights Watch senior researcher Tanya Lokshina, who said she was asked by the embassy to transmit the message.

The meeting with rights groups came after the United States on Thursday told China it was upset it did not hand over Mr Snowden after he fled to Hong Kong, saying that the decision had undermined relations.

President Barack Obama, meeting senior Chinese officials who were in Washington for annual talks, "expressed his disappointment and concern" over the Snowden case, the White House said.