TRIPOLI (AP) ― Libya’s parliament ousted Western-backed Prime Minister Ali Zidan in a Tuesday vote, removing the first democratically chosen leader who had struggled for 15 months to stem the country’s spiraling descent into chaos, with divisive political power struggles and rampant militias out of the control of the weak central government.

The government has been paralyzed for months by the power struggle between Islamists in parliament trying to remove Zidan and anti-Islamist political factions ― each side backed by rival militias. Zidan’s removal came as another fault line in the country was rumbling ― between the central government and the restive eastern half of the country, where many are demanding greater autonomy, with each side again backed by their own militias.

On Tuesday, a powerful militia from the western city of Misrata clashed with a rival eastern militia outside the central city of Sirte in heavy fighting, on a drive to take control of the oil terminal of al-Sidra, further east along the coast.

The eastern, pro-autonomy militia, headed by a commander named Ibrahim Jedran, has controlled al-Sidra and other oil facilities in the east for months in defiance of the central government, shutting down exports of the country’s biggest revenue earner. This week, Jedran’s militia sought for the first time to export oil itself, with a North Korean-flagged tanker docked at one of the ports it controls, al-Sidra. 

Pro-government militias claimed Monday to have recaptured the tanker, a claim the militia holding the port denies. The status of the tanker has not been independently confirmed, but officials in the capital Tripoli have vowed to rally their forces to retake not only al-Sidra, but also the other facilities held by Jedran’s fighters ― a move that could spark wider fighting with the east.

A group of pro-autonomy leaders of eastern tribes issued a statement Tuesday warning that the clashes and the drive to take back the oil facilities could push them to increase their demands to “separation” for the eastern region, known as Barqa. “We are not responsible for any repercussions,” they warned, saying they support Jedran’s forces and its bid to sell the oil.

From the other camp, Col. Hassan Shaka claimed his forces had taken Sirte and told the LANA news agency his fighters would continue east to retake the oil terminals.

Zidan has appeared particularly helpless in recent days in trying to deal with the crisis over the oil tanker. He confessed to reporters on Saturday that the nation’s military does not carry out his orders and complained that “everyone is working against the government.”

After the “no” vote carried Tuesday vote of confidence, parliament named the defense minister, Abdullah al-Thinni, as interim prime minister until a replacement for Zidan is found.

Zidan was Libya’s first prime minister chosen by an elected parliament after the 2011 revolt that removed and killed longtime strongman Moammar Gadhafi. Gadhafi’s 42-year rule left Libya with no strong state institutions. Zidan has presided over a government that has little authority and is frequently subjected to humiliations.

In the absence of a strong military and police force, the state relies on militias to keep order ― but many defy the government, with one of them briefly abducting Zidan himself last year. Further fueling the turmoil, militias have lined up behind the Islamist and anti-Islamist camps, often throwing the political disputes into violence.

Islamists in parliament have been trying for months to remove Zidan, who was elected to the post in late 2012. They were finally able to do so Tuesdsay by making his removal part of a package that includes new parliamentary elections, said Islamist lawmaker Mohammed Bu Sedra and Nouri al-Gamal, a lawmaker from the main anti-Islamist bloc, the National Forces Alliance.

Elections have been a demand by many Libyans since parliament‘s mandate ran out in February, and the package won over enough votes to back Zidan’s removal. The “no” vote won the support of more than 120 of the approximately 180 lawmakers who remain in the legislature, several parliament members said.

Zidan had no immediate public reaction to the vote. But in an interview recorded Tuesday before his ouster, he told the Libyan Al-Ahrar TV that if parliament withdraws confidence “I will be very happy because they would help me get out of this hard responsibility.” He said a faction in parliament perceives him as a “secularist” or “non-Islamic” and wanted to remove him from his post from the start, adding, “I believe in God ... but there are people who using religion as a political tool.”

New parliament elections could be a set-back for the Islamist camp. Speaking to the Associated Press, Mohammed Gair, a leading member of the Muslim Brotherhood, acknowledged that the group has lost popularity amid the failures of the parliament since it was elected in 2012.

But suspicions of the Islamists are high. In the eastern region, several figures in the autonomy movement saw Zidan’s removal as power grab by the Islamists. That and the militia battles outside al-Sidra raise the potential for an escalating fight between the central government and western-based militias on one side and eastern-based militias on the other.

The east, centered on Benghazi, Libya’s second largest city, has long complained of discrimination by Tripoli. The autonomy proponents are calling for a federal system that gives considerable self-rule to the regions and a fairer sharing of resources -- particularly the oil wealth.

“They want to bring their own men to monopolize power,” Bereka Beltamr, a member of an autonomous Barqa council. “We are expecting anything to happen now.”