Baghdad, Iraq ? A new round of car bombings and other violence struck Iraq on Wednesday, with 55 people killed or found dead.

The relentless attacks indicate how difficult it may be for the Iraqis to replace U.S. forces in the capital. The scope of the problem was clear Wednesday, from the first bombing at a bus stop during morning rush hour through the announcement at 9 p.m. that the tortured, bullet-ridden bodies of 21 kidnap victims had been found on the streets of the capital.

“If you take Baghdad, it’s unacceptable levels of violence here right now. We have got to bring it down,” said Maj. Gen. William Caldwell, the top American military spokesman in Iraq.

The violence came ahead of a national reconciliation conference scheduled for Saturday. The gathering is aimed at rallying ethnic, religious and political groups around a common strategy for handling Iraq’s problems.

At least 17 people were killed Wednesday in car bombings against Shiite and Sunni targets in Baghdad.

The first major attack happened at 8:45 a.m., when a car bomb exploded near a Shiite mosque in the Kamaliyah neighborhood, killing at least 11 civilians, wounding 27 and heavily damaging shops and cars, authorities said. They said the mosque was not damaged.

“A Volkswagen car exploded right near the bus stop, hitting a group of people, including women and children who were waiting to take a bus to a fruit and vegetable market,” said one witness, Abu Haider al-Kaabi.

Two other car bombs exploded in the mostly Shiite area of New Baghdad, killing four people and wounding 14. Another car bomb struck the largely Sunni area of Yarmouk, killing two people and wounding three.

North of Baghdad, seven tortured bodies were found in Mosul, two people were killed by roadside bombs in Kirkuk and men with explosives destroyed a small, empty Shiite shrine in Baqouba, security forces said. Two suicide car bombs also struck the headquarters of the Iraqi army’s 2nd Battalion near Kirkuk, killing four soldiers and wounding 10.

On the political front, Iraq’s prime minister is weighing whether to sever his alliance with a radical Shiite cleric blamed for much of the country’s sectarian violence, aides said Wednesday. But isolating Muqtada al-Sadr could lead to more deadly attacks, even if the strategy could produce a more stable administration over time.

Prime Minister Nouri al-Maliki has been meeting over the last three days with a small circle of his Dawa Party stalwarts to discuss their options, according to his aides who spoke on condition of anonymity because the subject is sensitive.

The meetings began after reports surfaced of a proposed realignment of the alliance supporting the governing coalition, the aides said.

The White House has acknowledged efforts to shore up al-Maliki’s coalition but has denied that the move is aimed at replacing him, though some of his aides fear this is the goal.

“We’ve talked in recent days about a moderate bloc that has Sunni, Shia and Kurdish leaders,” White House spokesman Tony Snow said Wednesday.

Central to that strategy is to curb the power of al-Sadr, the radical anti-American cleric who controls 30 of parliament’s 275 seats, five Cabinet ministries and the Mahdi Army, Iraq’s biggest and most active Shiite militia.

There has been no contact between al-Maliki and al-Sadr since word of the possible new alignment surfaced this week, the aides said.