Police raided more than 20 government buildings and private offices, seeking evidence in a series of criminal investigations of Prime Minister Ehud Olmert, potentially weakening his position ahead of a crucial Middle East peace conference in the US.
The early Sunday morning sweep came just as Olmert's popularity, which plummeted after last year's inconclusive war against Lebanese Hezbollah guerrillas, has begun to rebound.
The raid on Sunday targeted more than 20 locations, including the Industry and Trade Ministry, the Postal Authority as well as Jerusalem's City Hall police spokesman Mickey Rosenfeld said.
"Police investigators are searching a number of government and private offices in connection with three ongoing investigations [into Olmert]," Rosenfeld said.
Plainclothes police hauled cardboard boxes full of files out of the offices and loaded them into police vehicles -- a scene that has been repeated several times in recent years during police investigations of Israeli prime ministers.
Benjamin Netanyahu, prime minister from 1996 to 1999, was the object of suspicions that he misused power and improperly appropriated government gifts. His successor, Ehud Barak, was suspected of illegal campaign financing. Ariel Sharon, who served from 2001 until he was disabled by a stroke last year, was targeted by several police inquiries, including probes on campaign finance and real estate irregularities.
None of the prime ministers was formally charged. Barak is now the defense minister, and Netanyahu, leader of the hard-line Likud opposition party, is a leading candidate for prime minister again.
Olmert's office would not comment on Sunday's raids, but in the past he has often insisted he has done nothing wrong, dismissing the investigations as a political witch hunt.
Olmert is preparing for a Middle East peace conference later this month in Annapolis, Maryland. He hopes the gathering will launch formal peace talks with the Palestinians after a seven-year lull.
A criminal indictment of Olmert would deal a heavy blow to the peace efforts. Although he would not be forced to step down, he would be seriously weakened and likely face intense public pressure to step aside.
In one case, the prime minister is suspected of buying a luxurious Jerusalem home at a substantial discount from a developer in exchange for arranging construction permits for the builder. Olmert was once mayor of Jerusalem.
In a second case, police are looking into suspicions that while he was trade minister Olmert steered a government grant to a friend and arranged improper political appointments.
The prime minister is also suspected of trying -- unsuccessfully -- to rig the sale of a bank in favor of two associates while he was finance minister.
Investigators were still collecting evidence late on Sunday afternoon and the search was expected to continue into early evening, Rosenfeld said.
He said police expected to confiscate documents and other materials, but gave no further details.