Bolivia's President Evo Morales has said he would grant asylum to former US intelligence contractor Edward Snowden, if the US whistleblower, who is believed to be holed up at Moscow airport, requests it.

Morales said on Saturday that his offer is a protest against the US and European nations whom he accused of temporarily blocking his flight home from a Moscow summit on the suspicion that Snowden was on board.

Declaring that Bolivia has "no fear" of the US and its European allies, Morales said that he would be willing to give asylum to Snowden, if he asked.

Morales' offer came after two other leftist Latin American leaders - Venezuela's Nicolas Maduro and Nicaragua's Daniel Ortega - also said that they would help the US fugitive, who leaked a trove of secret documents outlining NSA's surveillance programme.

"As head of state of the Boliviarian republic of Venezuela, I have decided to offer humanitarian asylum to the young Snowden ... to protect this young man from the persecution launched by the most powerful empire in the world," Maduro said on Friday.

The Nicaraguan leader said, he could accept an asylum request from Snowden "if circumstances permit", but did not elaborate on the conditions that would allow him to offer the asylum.

The offers have raised hope the US whisteleblower might be finally able to leave Russia, though it remains unclear how exactly Snowden could reach another country without legal documents. The US revoked his passport after he fled to Moscow from Hong Kong.

Snowden apparently applied to 21 countries for asylum, but most of them have since declined to accept his request.

His bid for Icelandic citizenship hit an impasse earlier on Friday when the country's parliament voted not to debate it before the summer recess.