A group of European ambassadors flew into Libya's capital Thursday for the first time since 2014 to support the unity government's struggle to end years of chaos exploited by jihadists.

French ambassador Antoine Sivan, Peter Millett of Britain and Spain's Jose Antonio Bordallo held talks with the Government of National Accord (GNA) at the Tripoli naval base where it has set up operations.

A car bomb attack on a security post in the Libyan city of Misrata on Wednesday left one dead and four wounded, local government and medical sources said.

The municipal council of Misrata, 200 kilometers (120 miles) east of Tripoli, said the post in the Saddada area was the target of "a cowardly terrorist attack" that killed one guard.

Around 50 countries and international organizations met in Tunis on Tuesday to discuss "international support" for a new unity government in neighboring Libya.

The one-day meeting sponsored by the United Nations and Great Britain aims to allow representatives of the U.N.-backed authority to outline its priorities to rebuild the country's economy after five years of turbulence.

President Barack Obama says the biggest mistake of his presidency was a lack of planning for the aftermath of the fall of late Libyan leader Moammar Gadhafi, with the country spiraling into chaos and grappling with violent extremists.

Asked in a Fox News interview aired Sunday to name the "worst mistake" of his presidency, the U.S. leader said it was "probably failing to plan for the day after what I think was the right thing to do in intervening in Libya."

Libya's coastguard on Monday rescued 155 migrants east of Tripoli who had been trying to reach Europe by boat, an official said.

"We were told that a boat with people of African nationalities on board was in trouble off Ghout Rumman," coastguard Colonel Ashraf al-Badri said, adding that the information came from fishermen.

Libya's new unity leaders worked to tighten their hold on Tripoli Thursday, taking over the website of a rival authority in the capital whose head is refusing to stand aside.

A week after arriving by sea with a naval escort, the U.N.-backed unity cabinet appears to be winning the support of key institutions that control Libya's wealth and, crucially, militias in the capital.

Libyan prime minister-designate Fayez al-Sarraj, who is facing the huge task of uniting a country ravaged by divisions, is a novice politician but comes from a family with deep political roots.

The U.N. Libya envoy traveled to Tripoli and met the new prime minister designate Tuesday, in the latest sign an internationally backed unity government is asserting its authority over the capital.

Martin Kobler flew into Tripoli for his first visit since Fayez al-Sarraj arrived with members of his cabinet in the capital last week.

Libya's National Oil Corporation has thrown its support behind a UN-backed unity government, a key pledge to a cabinet rejected by rival forces who seek to control the country's oil wealth.

Founded in 1970, the NOC is based in the capital Tripoli where Libya's Central Bank -- the depositor of the country's oil wealth -- also has its headquarters.

Libya's U.N.-backed unity government has won increasing pledges of loyalty as it gradually exerts its authority in the face of strong opposition from rival political forces in the conflict-wracked country.

Libya's warring sides are under intense international pressure to cede power to prime minister-designate Fayez al-Sarraj, whose arrival in the capital on Wednesday angered a rival Tripoli-based government.