U.N. envoy Martin Kobler expressed concerns Wednesday that Libya's political process is slower than the Islamic State group's expansion, after the country's internationally recognized authorities rejected a national unity government.

World powers have urged Libya's warring factions to endorse the unity government agreed last week under a U.N.-brokered deal aimed at ending political paralysis that has fueled the rise of jihadists.

The EU is considering sanctions against several Libyan figures for undermining efforts to form a national unity government, a key first step towards bringing peace to the war-torn country, European sources said Tuesday.

The European Union has repeatedly warned it would impose sanctions against anyone "spoiling" a Brussels-backed peace process, amid growing concerns Islamic State (IS) jihadists could use oil-rich Libya as a springboard to attack Europe.

Seen as an anti-Islamist hero by some and a threat to peace by others, the fate of Libya's army chief has emerged as a stumbling block to efforts to forge a unity government.

General Khalifa Haftar, 73, presents himself as Libya's savior in the face of a growing jihadist threat, but is himself a hugely divisive figure.

Libya's internationally recognized parliament voted Monday to reject a UN-backed unity government, in a major blow to international efforts to end the country's unrest.

The United Nations and Western diplomats have urged Libyans to back the unity government formed last week as a step toward ending the political chaos that has gripped the country since the 2011 ouster of longtime dictator Moammar Gadhafi.

An Italian ship on Saturday morning reached the Sicilian port of Catania bringing 246 migrants to safety as well as the body of another after two rescue operations off the coast of chaos-wracked Libya, the coastguard said.

The Dattilo ship had on Thursday and Friday rescued 131 and 115 migrants trying to reach Europe on two inflatable boats.

Italy said Tuesday it was treating 15 Libyan police officers injured in a January 7 truck bombing that has been claimed by the Islamic State group.

The attack on a police training center in Zliten, a coastal city about 170 kilometers (100 miles) east of Tripoli, killed 50 people and injured over a hundred.

The Islamic State group has claimed a deadly suicide bombing at a checkpoint in Libya's oil heartland, as EU foreign affairs chief Federica Mogherini seeks to shore up support for a unity government.

Fears that the jihadists are establishing a new stronghold on Europe's doorstep have added urgency to efforts to bring together warring factions in a country beset by years of turmoil.

Former British prime minister Tony Blair urged Moammar Gadhafi to stand aside and find a bolthole in the early days of the Libyan uprising, telephone transcripts released Thursday showed.

Blair urged the Libyan dictator to stop the violence, start a process of change, stand aside, resolve the situation peacefully and keep communications open between them.

A suicide truck bombing on a police school in Libya's city of Zliten killed more than 50 people Thursday, in the deadliest attack to hit the strife-torn country since its 2011 revolution.

A bomber detonated an explosives-laden truck used for carrying water at a police training center in central Zliten at around 8:30 am (0630 GMT), a local security source told AFP.

At least four petroleum storage tanks were set ablaze during deadly fighting as the Islamic State group tries to seize coastal export terminals in eastern Libya, the National Oil Company said Wednesday.

The fighting, in which at least 10 security guards have died, began Monday as U.N. Libya envoy Martin Kobler struggles to convince the oil-rich North African country's rival parliaments to agree on a unity government deal brokered by the world body.