NEW YORK (Reuters) - Three rights groups launched a campaign on Wednesday to try to persuade President Barack Obama to pardon former National Security Agency contractor Edward Snowden on U.S. theft and espionage charges before Obama leaves office in January.

The American Civil Liberties Union, Amnesty International and Human Rights Watch said the time was right to rally support for a pardon for Snowden, who leaked documents about top-secret U.S. surveillance programs to journalists in 2013, fled to Hong Kong and was granted asylum in Russia. The ACLU provides legal representation for Snowden.

Speaking on Wednesday via video, Snowden told a news conference in New York City that he was “comfortable with the decisions I made” but whether or not he gets a presidential pardon is not up to him.

“I do not myself ask for a pardon and I never will,” Snowden said.

Snowden said he could not receive a fair trial in the United States because a law he was charged under, the 1917 Espionage Act, does not let him explain to a jury his reasons for leaking.

“This World War I-era law does not distinguish between those who freely give critical information to journalists in the public interest or spies who sell it to a foreign power for their own,” said Snowden, who lives in Moscow.

A pardon now may make sense for Obama, the groups said, because he may be seeking to burnish his legacy and be able to act with less concern for politics. Obama, a Democrat, will leave office at the end of his second, four-year term on Jan. 20.

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“Presidents normally take some of the most difficult actions of their eight years in office in the final months,” Anthony Romero, the ACLU’s executive director, told the news conference.

Snowden was charged by U.S. federal prosecutors in 2013 with theft of government property, unauthorized communication of national defense information and willful communication of classified communications intelligence to an unauthorized person.

The campaign for a pardon includes a website, www.pardonsnowden.org, that people can use to write to the White House, and the groups ran ads in the Washington Post and Politico newspapers, saying Snowden exposed unlawful programs and prompted reforms.

The campaign coincides with the release of a film, titled “Snowden,” directed by Oliver Stone.

It also comes at a time when U.S. authorities are investigating whether hackers backed by Russian spy agencies have been interfering with the U.S. presidential campaign by stealing and releasing documents and emails principally to embarrass Democratic candidate Hillary Clinton.

U.S. officials have said they will not budge on their demand that Snowden be prosecuted for stealing thousands of classified intelligence documents, the release of which they say damaged national security.

White House spokesman Josh Earnest said on Monday that Snowden is charged with “serious crimes, and it’s the policy of the administration that Mr. Snowden should return to the United States and face those charges.”

The House of Representatives intelligence committee on Thursday was scheduled to hold a closed-door meeting to vote on a report it has prepared examining Snowden’s background and activities. While most of the report is expected to remain classified, a congressional official said the panel will also vote on whether to publicly release an unclassified summary.