BAGHDAD - The death toll from twin car bomb blasts in a crowded Baghdad market rose to 51 Thursday, police said, and the country's main Sunni political party condemned the attack on a heavily Shi'ite Muslim area.

The car bombs Wednesday, which also wounded 76 people in the capital's sprawling Sadr City slum, followed a series of other attacks in the past two weeks that have stirred fears of a return to broader sectarian bloodshed in Iraq.

A third car bomb was found in a parked taxi cab and detonated by security forces.

The Iraqi Islamic Party, the main political party in parliament representing the country's once dominant Sunni minority, denounced the attack as a blatant attempt to trigger renewed fighting between Sunnis and Shi'ites.

The bloody hands want Iraqis to feel fear, the party said in a statement.

These explosions in Sadr City are part of a big conspiracy by Iraq's enemies. We call on all political groups and the Iraqi government, and especially the security forces, to quell this sedition.

The upsurge in violence this month has ended the sense of growing calm and security that had gripped Baghdad earlier this year.

While the violence remains below the levels of last year, the attacks coincide with plans for U.S. combat troops to pull out of Iraqi cities in June, ahead of a full withdrawal from Iraq by the end of 2011.

Iraqis still lack faith in the abilities of their own security forces to defend them against bombs and other attacks.

Many Iraqis also fear there will be more violence ahead of a national election late this year, as political rivals and armed groups jostle for dominance of the oil-producing country.

U.S. President Barack Obama said Wednesday the string of recent deadly bombings was a cause for concern, but the political system was functioning and violence was low compared to a year ago.

Analysts said Iraq is likely to suffer suicide and car bomb attacks for several more years. While that will certainly present a dire threat to Iraqi civilians, it is less clear whether it presents a mortal threat to the state.

More dangerous to Iraq's medium-term stability than bombs is the fact not enough has been done in the political arena to foster reconciliation between Sunnis and Shi'ites, the analysts say.

Iraq has also failed to take steps to ease tensions over land and oil between Arabs and minority Kurds in the north.

Iraq