Baghdad  - The Iraqi government Friday called on all parties in the northern city of Kirkuk to remain calm, a day after Kurdish councilors called for the city to become part of the largely autonomous region of Kurdistan.

Government spokesman Ali al-Dabbagh urged people to obey the law and the constitution and avoid any escalations that may damage national unity.

"The Iraqi government stresses its rejection to any individual step to change the situation in Kirkuk, and considers it illegal and unconstitutional," he said in a statement.

Tensions have been rising over the city's fate, with many people demonstrating against provincial elections law passed by the parliament last week. Angry Kurds are objecting to the law which calls for a secret ballot to decide a power-sharing arrangement in the multi-ethnic city of Kirkuk.

"Only constitutional mechanisms and political consensus determine Kirkuk's destiny. The government warns that any violation or security disturbance committed by any armed group will be dealt with in all firmness and force, according to the law," he was quoted as saying by Voices of Iraq (VOI) news agency.

Al-Dabagh said people should not allow Iraq's "enemies" to make use of the situation. Al-Qaeda has sought to exploit the divisions in the city to fan tensions.

A bomb exploded Friday in Kirkuk targeting the motorcade of the chief of the city's police. Chief Jamal Taher survived the attempt, a security source said.

Last Monday, 22 people were killed and 150 injured when a suicide bomber blew himself up among protestors.

In last week's parliament session, Kurdish lawmakers walked out in protest at the law, but Iraqi legislature approved the law despite the walkout.

Kurdish parliament members promised to have the law rewritten and denounced the measure as "unconstitutional."

Speaker of the Iraqi Parliament Mahmoud al-Mashhadani Wednesday announced the end of the current legislative term, noting that an 'extraordinary' session will be held Sunday to debate the controversial elections law.

Turkish Prime Minister Recep Tayyip Erdogan expressed his concern to Iraqi President Jalal Talbani late Thursday on Kurdish claims of annexing Kirkuk to the semi-autonomous region of Kurdistan.

Kirkuk is the centre of the northern Iraqi petroleum industry. It is a historically and ethnically mixed city populated by Assyrians, Kurds, Arabs and Iraqi Turkmen. According to VOI, its population was estimated at 1,200,000 in 2008. (dpa)