LIBYA’S top court ruled today that parliament’s contested vote for the new prime minister was unconstitutional.

The Supreme Constitutional Court offered no further details or instructions but the Islamists who pushed for Ahmed Maiteg’s appointment — as well as the short-lived prime minister himself — said they would abide by the decision.

It was a rare peaceful resolution in a country that has been plunged into chaos between competing warlords and militias following the Western-orchestrated civil war that ousted long-time leader Muammar Gadaffi.

Mr Maitag — a wealthy businessman who owns a luxury hotel in Tripoli — took control of government buildings last week backed by Islamist militiamen after Abdullah al-Thinni refused to leave office.

The interim prime minister had rejected the legitimacy of the vote appointing Mr Maitag, which saw secular MPs walk out and Islamists secure votes from legislators that opponents said were not present.

Twelve MPs took the case to the supreme court to challenge the vote.

Mr Maiteg insisted he would “be the first to submit to the court decision and respect the judiciary.”

He added: “What happened today is that we have made important gains toward building a state of law and institutions that we all are seeking.”

Saleh al-Makhzoum, the second deputy of parliament and member of the Muslim Brotherhood’s Justice and Construction Party, said parliament would comply with the decision for the sake of the “state of law.”

Mr Makhzoum added: “From this moment … Abdullah al-Thinni is the caretaker prime minister until parliament learns the court’s reasons for deciding that Maiteg’s election was unconstitutional.

Parliament was expected to discuss the matter today.

Meanwhile, renegade General Khalifa Haftar has warned he will arrest Islamist MPs to end the turmoil in Libya.

The serial coup-plotter was still ploughing on with his offensive against the Islamist militias that he blames for the chaos engulfing the country.

He has spent the last few weeks bombarding Islamist militias, which have in turn attacked his forces, including in a failed assassination attempt that killed four people.