Mahmud Mashhadani, speaker of the Iraqi parliament

Iraq's parliament has delayed a debate on Shi'ite proposals to create an autonomous region in the south of the country.

Iraqi officials say the session was postponed because of strong opposition by Sunni political parties, which argue that federalism will lead to the break up of the country.

The main Shi'ite political bloc in parliament, the United Iraqi Alliance, has submitted a bill calling for a three-way federal system in Iraq with an autonomous region in southern, mostly Shi'ite, Iraq. There is already a Kurdish autonomous region in the north.

Iraq's Sunni Arab minority also fears the proposals will place the country's oil resources in the hands of Shi'ites and Kurds.

In other development, Iraqi police say at least 18 people died in various attacks Sunday .

Also Sunday, officials said a visit to Iran by Iraqi prime minister Nuri al-Maliki has been delayed.

The visit was to take place on Monday. An Iraqi official blamed the delay on what he called "technical reasons."

Elsewhere, Iraqi police raided a building, killing three al-Qaida operatives. A fourth got away. The police say they found a large quantity of explosives during the raid.

Separately, Iraqi police found the bodies of at least eleven victims of political violence.

Some information for this report was provided by AFP, AP.