A top official with the U.S. State Department said Sunday that the flood of diplomatic documents made public by WikiLeaks has serious consequences, including possibly putting anyone who speaks to U.S. diplomats at risk.

Philip J. Crowley, the U.S. Assistant Secretary of State for Public Affairs, told CTV's Question Period Sunday that the Internet whistle-blower site has harmed the careers and even the safety of innocent people.

"Julian Assange is wrong and has really done great damage … in exposing these classified documents he is putting (our) sources at risk," Crowley said.

"We have reached out to people around the world with whom we interact and have warned them about the potential ramifications.

"We are going to be watching this closely."

Crowley said at the very least some U.S. diplomats may have to be moved to other posts as a result of documents released by WikiLeaks.

"We may well have to reassign some of our diplomats and a couple of our ambassadors," he said. "There's no question that this has done substantial damage."

The U.S. is currently conducting a criminal investigation into WikiLeaks' release of the diplomatic cables and memos.

The latest batch of leaked diplomatic documents is casting a pall over the NATO mission in Afghanistan.

Diplomatic memos posted by WikiLeaks quote European Union President Herman Van Rompuy as saying that the EU no longer believes in success in Afghanistan, and that European troops are still there "out of deference to the United States."

The comments were made to Howard Gutman, the U.S. ambassador to Belgium, according to the leaked memo.

According to the memo, Van Rompuy said in December 2009 that the Europeans will wait until the end of 2010 to see if there has been progress made in Afghanistan.

"If it doesn't work, that will be it, because it is the last chance," Van Rompuy, a former Belgian prime minister, reportedly said.

Several documents released by WikiLeaks have contained criticism of corruption in the Afghan government by diplomats from NATO nations, including Canada's ambassador to Afghanistan.

The Internet whistleblower site has been releasing hundreds of diplomatic notes, cables and memos over the past week, setting off a storm of controversy and drawing the ire of governments around the world.

But Crowley said U.S. relations with at least one country have not been harmed by WikiLeaks' revelations: Canada.

"If the greatest concern between our two countries is what's on Canadian television then we're doing pretty well," he said.

The leaks, which embarrassed Washington and foreign leaders with their often brutally frank language, have brought official and unofficial pressure to bear on WikiLeaks and its founder.

The site has become an Internet pariah of sorts and has had its account with the online payment service PayPal cut off.

The U.S.-based Amazon.com kicked WikiLeaks from its servers Wednesday, forcing it to move back to a Swedish provider, and other servers stopped directing traffic to WikiLeaks because of continuing cyber attacks on the site that threatened the rest of their networks.

The organization found a new online home in France, but that too went offline Sunday.

WikiLeaks has been brought down numerous times this week by what appear to be denial-of-service attacks.

With files from The Associated Press