Iraq's parliament voted on Tuesday to reject Kurdistan Regional Government (KRG) independence referendum planned for Sept. 25, authorizing the prime minister to take all measures to preserve Iraq's unity, a lawmaker said.

"Kurdish lawmakers walked out of the session but the decision to reject the referendum was passed by a majority," Mohammed al-Karbouli said.

Kurdish lawmaker Majid Shingali said Kurds would reject the decision.

"This decision has no value and we will not implement it," he told Reuters.

Iraqi Prime Minister Haider al-Abadi's government had previously rejected the referendum as unilateral and unconstitutional.

The United States and other Western nations fear the September vote in Iraqi Kurdistan could ignite a new conflict with Baghdad and possibly neighboring countries, diverting attention from the war against Daesh terrorists in Iraq and Syria.

Turkey, along with Iraq, Iran and Syria, also opposes the idea of Iraqi Kurdish independence. Ankara has opposed the independence vote, calling it a "grave mistake" that would "result in undesired results" for regional peace and security.

With a population of around 5 million people, Iraq's Kurdish region already enjoys a high degree of autonomy. It has its own parliament and armed forces, but has clashed with the central administration in Baghdad over distribution of oil revenues and control of some areas under the central Iraqi administration.