Human Rights Watch has urged countries where American whistle-blower Edward Snowden seeks asylum to consider his claim "fairly and protect his rights under international law".
"Any country where Snowden seeks asylum should consider his claim fairly and protect his rights under international law," Human Rights Watch said in a statement.
"It may be that some countries most likely to resist US pressure to return him for prosecution themselves have poor records of protecting their own critics and dissidents.
"But that would be no reason for them to disregard the requirements of international refugee law in Snowden's case," it added.
Former National Security Agency consultant Snowden's disclosures about the massive surveillance of communications data by the US and Britain point to a serious infringement on the right of privacy.
"If true, these disclosures indicate that data is being collected about the communications, associations, and movements of millions of ordinary people who aren't suspected of wrongdoing or considered a threat.
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"This indiscriminate collection of data ... cannot be justified by some future hypothetical usefulness against potential threats to these countries," Human Rights Watch said.
India and Brazil are among the countries that have declined to give asylum to Snowden, who is now holed up at the Moscow airport.
Human Rights Watch said US whistle-blower protections fall far short of these standards for people who disclose abuse in the national security arena.
US law simply does not provide national security whistle-blowers with adequate protection from retaliation or punishment for disclosures in the public interest.
Snowden faces various charges in US federal court, some of which could carry lengthy prison sentences. These include charges under the antiquated US Espionage Act.
It said Snowden could base a claim for asylum on the grounds that, if he were returned to the US, he would face serious harm on account of his political opinion - his view that the public must be informed of massive government intrusion on privacy rights.
Human Rights Watch said any country that speaks up in Snowden's defence should also guarantee the free speech rights of its own citizens, critics and whistle-blowers, and the right of its own people to freedom of information.
"The US should also keep in mind that for many decades it has offered political asylum to people who suffer severe penalties for criticizing their governments.
"It should not apply a double standard by working against other governments that might extend asylum in this case."