BEIRUT – A Lebanese newspaper's website has been shut down following a hacker attack, apparently over its publishing of leaked U.S. diplomatic cables, an editor with the daily said Thursday.

Omar Nashabe said he doesn't want to speculate who is behind what he called the most serious attack on the Al-Akhbar newspaper since it was established in 2006.

The privately owned Al-Akhbar is close to Lebanon's militant Hezbollah group and its allies. WikiLeaks gave the paper an advance copy of secret U.S. diplomatic documents, and Al-Akhbar has been publishing the cables since last week.

On Thursday, the paper published a document about corruption in the north African Arab nation of Tunisia. The U.S. memo focused on alleged corruption inside President Zine El Abidine Ben Ali's family.

Last week, Al-Akhbar printed another diplomatic cable saying that Lebanese Defense Minister Elias Murr offered U.S. officials advice on how Israel could defeat Hezbollah in a future war. The memo also said Murr vowed to keep the Lebanese army out of the fighting.

Murr's office denied he had made the comments, and said the report was "out of context and inaccurate."

Lebanon's daily An-Nahar quoted Jeffrey Feltman, the assistant secretary of state for Near Eastern affairs, as telling a group of Arab journalists during a telephone conference that the diplomatic cables may by used to instigate strife in Lebanon.

The leaks have raised tension between U.S.-backed groups and their Syrian-supported rivals.

Feltman warned that some Lebanese might be harmed for cooperating with the United States, according to the paper whose correspondent in Washington took part in the telephone conference.

Nashabe, the editor, said the paper is trying to reactivate the website and plans to investigate the attack. He says the website has been inaccessible since about 4 a.m.