Washington, Jun 29 (PTI): The United States continued with its diplomatic effort to get back Edward Snowden, who is wanted in the country on the charges of espionage and leaking classified documents, with various countries including Russia, a US official has said.

"We continue to be in touch via diplomatic and law enforcement channels with countries through which Snowden might transit or that could serve as a final destination," the State Department spokesperson, Patrick Ventrell, told reporters at his daily news conference on Friday.

"Also in touch, clearly, with the Russian authorities, and we're advising governments that Snowden is wanted on felony charges and should not be allowed to proceed any further other than necessary to return to the United States," he said.

Meanwhile, the House Majority Leader, Eric Cantor, alleged that the US President Barack Obama is not serious in getting back Snowden.

"I think the President's remark was kind of flippant. I don't think he gives justice to this grave matter that the country's facing. This is a serious issue. Already our authorities have said he has broken the law. There is potential grave national security issues at hand," Cantor said.

"I am shocked that the President has not picked up the phone and weighed in with the President's of China and Russia to protect American national security. This is not some ordinary matter of law enforcement. This is our country's national security," he said.

Snowden has been charged with espionage, theft of government data and conveying classified information to unauthorised person.

If extradited to the United States and convicted in the court of law, he faces 10 years of imprisonment on each of these charges.

The documents leaked by Snowden, first published in The Guardian and The Washington Post, revealed details of the secretive programs of the US's National Security Agency about getting access to phone records of millions of Americans and getting internet usage details of suspected foreign terrorists.