BAGHDAD - Iraq's government said on Thursday that violence would increase before a parliamentary election due in January, a day after a car bomb killed at least 33 people at a marketplace in the country's south.

Prime Minister Nuri al-Maliki told a meeting of security chiefs in Baghdad that the blast in Al-Bathaa, a small town west of Nassiriya that had seen little violence, was a criminal operation with a political message.

Such attacks cast doubt on the ability of Iraqi security forces to stand alone after U.S. troops who invaded in 2003 withdraw from urban centers by the end of this month.

These operations will intensify...to try to make the elections fail, but they will not succeed, God willing, Maliki said.

The bloodshed had been orchestrated by those who wanted to see Iraq descend back into sectarian killing, he said.

The population realizes that there cannot be a return to sectarianism and fighting, he said.

Violence has fallen sharply across Iraq since its peak in 2006-07. But insurgents, including Sunni Islamist al Qaeda, continue to launch suicide and car bomb attacks like the one that ripped through Al-Bathaa in the Shi'ite Muslim south.

The parliamentary poll scheduled for January is likely to be a flashpoint, pitting Shi'ite parties against each other as well as against once dominant Sunnis and minority Kurds.

Iraqi security forces are confronting attacks on their own as U.S. soldiers quit towns and cities during June, as agreed in a pact between Baghdad and Washington. U.S. troops are due to end combat operations by the end of August 2010.

The security agreement came into effect at the start of this year but is supposed to be approved by a referendum before the end of July. Maliki's government wants to hold the referendum on the same day as the parliamentary vote next January.

The referendum is a part of law and discussions are ongoing among the ministers and the council of representatives, Interior Minister Jawad al-Bolani told reporters after a meeting with U.S. Ambassador Christopher Hill.

Bolani said Iraqi forces had arrested several people behind a string of bombings that rocked the capital in the last three months, as well as suspects in the Al-Bathaa explosion.

The region where the attack took place is very modest with very modest people, poor people, who are very deprived, so I can call it cowardly, he said. Our forces' reaction was immediate in detaining and arresting the ones who caused this attack.

(Writing by Daniel Wallis; Editing by Michael Christie and Angus MacSwan)

Iraq