More revelations about US and UK intelligence sources and practices expected to be published within days

This article is more than 9 years old

This article is more than 9 years old

The government has been warned by US authorities about the expected publication of sensitive diplomatic files on the whistleblower website WikiLeaks, Downing Street acknowledged yesterday.

Washington is braced for the release within days of thousands of documents on the website, which has previously published secret details of allied military operations in Iraq and Afghanistan.

"These revelations are harmful to the US and our interests," said the state department spokesman PJ Crowley last night. "They are going to create tension in relationships between our diplomats and our friends around the world."

David Cameron's spokesman this morning declined to discuss the nature of any confidential communications which may have been obtained by WikiLeaks.

The spokesman said: "Obviously, the government has been briefed by US officials, by the US ambassador, as to the likely content of these leaks.

"I don't want to speculate about precisely what is going to be leaked before it is leaked."

Washington could be embarrassed by the publication of candid and forthright assessments of foreign governments made by its officials.

Crowley warned that publication could erode trust in the US as a diplomatic partner.

"When this confidence is betrayed and ends up on the front pages of newspapers or lead stories on television or radio, it has an impact," he said.

The state department has known all along that WikiLeaks possesses classified documents, but it was not possible to predict exactly what information would be made public and what impact it would make, he said.

"We wish this would not happen, but we are obviously prepared for the possibility that it will," he said.