"We are all disturbed," the Arab League secretary general Amr Mussa told US reporters in Doha.

"We dont want Lebanon to get back to square one. We thought we already left this station," he told journalists accompanying US State Secretary Hillary Clinton in her Gulf tour.

He also called on the Iran-and Syria-backed Shia Hezbollah militia, without naming it, to stop believing that it is targeted by the special tribunal investigating the assassination of Hariri, and that all work should focus on reaching a compromise to maintain a stable government.

"All of us, Arabs, Europeans and yourselves (United States) will have to work in order to reach a kind of compromise that would maintain the possibility of having a stable government in Lebanon," Mussa said.

"Number two: avoid the pitfalls emanating from the belief of one party that all actions, including the tribunal, are but political ploys," he said in a clear reference to Hezbollah which accuses the court of wanting its head.

"There was a crime and the crime should be investigated and the criminals should be punished... The tribunal should be above politics, the justice should have its way and Lebanon must have a government," he said.

Mussa expressed deep concerns about the current situation in Lebanon.

"The situation is bad, is tense, is threatening," he said.

Ten ministers representing Hezbollah and its allies in the unity government led by the son of slain Hariri, Saad, announced their collective resignation Wednesday.

An 11th minister close to the Maronite President Michel Sleiman also quit the 30-member cabinet, providing the minimum number of resignations required to topple the government.

For months, Hezbollah has been pressing the Western-backed Hariri to disavow the tribunal, which it says is a US-Israeli ploy.

Press leaks have said the tribunal is poised to indict senior Hezbollah members in connection with the assassination. The militant group has warned any such accusation would have grave repercussions in Lebanon.