Ecuador is reviewing Edward Snowden's asylum request and will make a decision on the former US intelligence contractor "in due time" based on human rights considerations above all, Foreign Minister Ricardo Patino said on Monday.

The South American nation's leftist government is in "respectful" contact with Russia but also taking into account the US government's position on the case, Patino told reporters during a visit to Vietnam.

"We will consider the position of the US government and we will take a decision in due time in line with the (Ecuadorean) constitution, the laws, international politics and sovereignty," Patino said.

At the start of his news conference in Hanoi, Patino read the formal asylum request from Snowden and compared his case with the "persecution" of US soldier Bradley Manning, who is accused of giving secret US data to the WikiLeaks website.

Snowden was on a flight from Hong Kong that arrived in Moscow on Sunday.

"We know that he's currently in Moscow, and we are ... in touch with the highest authorities of Russia," Patino said.

But WikiLeaks founder Julian Assange said late on Monday that Snowden had received refugee papers from Ecuador's government to secure him safe passage. "In relation to Hong Kong, Mr Snowden was supplied with a refugee document of passage by the Ecuadorean government," Assange told reporters from inside Ecuador's embassy in London where he has been hiding from arrest for more than a year.

Such papers did not necessarily mean that Snowden would be granted asylum in Ecuador, Assange said.

Snowden had been in hiding in Hong Kong for several weeks after he revealed information on highly classified spy programs.

Patino said Ecuador would not base its decision on its potential to damage the country's relationship with the United States.

"There are some governments that act more upon their own interests, but we do not," Patino said. "We act upon our principles."

Reuters-AP-AFP