US wants cooperation of countries where Snowden may go

Snowden, who leaked secret details of vast US telephone and Web surveillance programs to media outlets, left Hong Kong despite a US extradition request and the US authorities will "pursue relevant law enforcement cooperation with other countries where" he may travel, the US Justice Department said.

"The chase is on," California Senator Dianne Feinstein said as the Snowden affair grew vastly more complicated for President Barack Obama, potentially testing US relations with Russia and other nations.

"And we'll have to see what happens," she said.

Feinstein, chair of the Senate Intelligence Committee, said she has learned Snowden may have more material to leak -- "over 200 separate items" -- but how much is not certain.

"I think we need to know exactly what he has. He could have a lot, lot more. It may really put people in jeopardy. I don't know," she told CBS.

According to WikiLeaks, unidentified diplomats and Wikileaks legal advisers are escorting Snowden, 30, a former employee of National Security Agency contractor Booz Allen Hamilton, in his bid to secure political asylum in a country yet to be disclosed.

US authorities filed espionage charges against Snowden last week and asked Hong Kong, where he first fled, to detain him on a provisional arrest warrant.

But Snowden boarded an Aeroflot flight for Moscow on Sunday amid Russian media reports that he would fly to Cuba and eventually Venezuela.

Snowden left his home in Hawaii on May 20 and flew to Hong Kong, a semi-autonomous Chinese territory, from where he proceeded to leak details of the secret US intelligence programs to the Guardian and The Washington Post.

The leaks have embarrassed Obama's administration, which was forced to defend US intelligence agencies' practice of gathering huge amounts of telephone and Internet data from private users around the world.

New York Senator Chuck Schumer expressed disappointment on Sunday with Hong Kong for allowing Snowden to leave and with Russia for letting him go there.

Schumer said it was "very disappointing what Hong Kong has done" and it "remains to be seen how much influence Beijing had on Hong Kong.

"I have a feeling the hand of Beijing was involved here," he told CNN.

"What's infuriating here is Prime Minister (Vladimir) Putin of Russia aiding and abetting Snowden's escape," Schumer added. "Putin always seems almost eager to put a finger in the eye of the United States, whether it is Syria, Iran and now, of course, with Snowden.

"That's not how allies should treat one another, and I think it'll have serious consequences for the United States-Russia relationship," he said.

Schumer said he expected the US authorities would ask Russia to hold Snowden. "Whether Russia does that or not, I don't know," he said.

NSA chief Keith Alexander said meanwhile that Snowden's blowing the lid on US surveillance has forced a tightening of security on IT system operators like him.

The NSA is overhauling its operations to keep a closer watch on contractors like Snowden, who "betrayed the trust and confidence we had in him" and "stole some of our secrets," General Alexander told ABC television.

No red flags went up to detect that theft, Alexander said, and the NSA is working to overhaul things to prevent a repeat.

"Clearly, the system did not work as it should have," he said.

"We are now putting in place actions that would give us the ability to track our system administrators, what they're doing, what they're taking," he said.

Also, "we've changed the passwords," Alexander said. "But at the end of the day we have to trust that our people are going to do the right thing."

The NSA chief also repeated assertions that the ultimate goal of the surveillance programs is to prevent terrorist attacks and that some 50 plots around the world had been foiled so far thanks to the programs.