US officials are worried about what other secret documents the whistle-blowing website Wikileaks may possess and have tried to contact the group without success to avoid their release, the State Department said last night.
The group has publicly released more than 90,000 US Afghan war records spanning a six-year period.
The group also is thought to be in possession of tens of thousands of US diplomatic messages passed to it by an army intelligence analyst, media reports have said.
"Do we have concerns about what might be out there? Yes, we do," State Department spokesman PJ Crowley told a briefing, adding that US authorities have not specifically determined which documents may have been leaked to the organisation.
He said the State Department could not confirm the longstanding reports that Wikileaks is in possession of a large set of US diplomatic cables.
But the fact that the documents released to date contained a handful of State Department messages suggests that other secret diplomatic messages may have been included in data transmitted to Wikileaks, Crowley said.
“When we provide our analysis of situations in key countries like Afghanistan and Pakistan, we distribute these across the other agencies including to military addresses,” Mr Crowley said. "So is the potential there that State Department documents have been compromised? Yes."
Both Mr Crowley and White House spokesman Robert Gibbs urged Wikileaks and its founder, Julian Assange, not to release further classified US government documents.
Mr Gibbs, noting Wikileaks claims to have at least 15,000 more secret Afghan documents, told NBC's Today show there was little the government could do halt the release of the papers.
"We can do nothing but implore the person who has those classified top secret documents not to post any more," Mr Gibbs said. "I think it's important that no more damage be done to our national security."
Reuters