Lebanon opposition steps up pressure after UN report

"We appeal to the Security Council to quickly form a commission of inquiry that should have the broadest possible legal perogatives to shed light (on the assassination) and judge those responsible," opposition MPs loyal to Hariri said in a statement.

A UN report issued Thursday was sharply critical of an investigation carried out by Lebanese authorities, concluding that their probe "has neither the capacity nor the commitment to reach a satisfactory and credible conclusion."

It concluded that an "international independent commission" would be needed to determine who planned and carried out the attack on Hariri. But it said it was "more than doubtful" that such a panel could work effectively as long as the current heads of the Lebanese security services remained on the job.

"A sustained effort to restructure, reform and retrain the Lebanese security services will be necessary," the report maintained.

An outside investigation and the removal of Lebanon's security chiefs have been key demands of an emboldened anti-Syrian opposition in the weeks following the February 14 assassination of Hariri in a bomb blast here.