Pope Francis on Saturday urged the international community to act over a deadly surge in the numbers of migrants attempting to reach Italy via perilous sea crossings from north Africa.

The pontiff's appeal came at the end of a week in which more than 450 people are feared to have drowned in the Mediterranean and more than 11,000 other would-be immigrants to Europe have been rescued by Italy's coastguard, merchant ships or vessels involved in a much-criticized European Union maritime border patrol operation.

The U.N. said Friday it was trying to narrow differences between Libya's rival parliaments over an agreement aimed at forming a unity government to end unrest tearing the country apart.

The differences emerged in written observations by the two sides on the agreement envoy Bernardino Leon is trying to clinch, said Samir Ghattas, spokesman for the U.N. mission in Libya (UNSMIL).

Restoring stability in war-wracked Libya is the only way to put an end to the migrant crisis in the Mediterranean, Italian Prime Minister Matteo Renzi said Friday.

"It's a sea, not a cemetery. The problem in this moment is the situation on the ground in Libya," Renzi told a joint press conference with U.S. President Barack Obama at the White House, saying "peace and stability of Libyan institutions" needed to be restored.

More than 11,000 migrants have been rescued from the Mediterranean and taken to Italy in the past six days, coastguards said, with hundreds more expected Friday.

As the wave of refugees trying to get to Europe grows, the Italian navy said it managed to recapture an Italian fishing trawler that had been attacked by Libyan gunmen off the chaotic war-torn country.

Italy pleaded for more help Thursday to rescue migrants risking their lives to cross the Mediterranean, and demanded a "clear answer" from the European Union about where the refugees should be sent.

In the aftermath of the latest migrant tragedy that saw some 400 people drown on Sunday off Libya, Foreign Minister Paolo Gentiloni said Italy was shouldering nearly all of the burden for patrol and rescue.

Delegates from Libya's rival parliaments gathered in Morocco Thursday for what U.N. mediators demanded be a "final" push for a unity government to stem mounting jihadism and a desperate exodus of asylum-seekers.

Rival governments have battled for power in the North African country since last August and just Wednesday an air strike blamed on the internationally recognised administration hit an air base controlled by its opponent.

A U.N. envoy trying to broker a unity government in war-torn Libya condemned as "unacceptable" an air strike Wednesday targeting militia near the capital.

Bernardino Leon called for an investigation into who carried out the raid, as media loyal to authorities in the militia-held capital blamed warplanes of the internationally recognized government.

The prime minister of Libya's internationally recognized government appealed Wednesday for Russia's help in securing the lifting of an arms embargo on the conflict-torn nation

Abdullah al-Thani asked for Moscow's assistance in removing the United Nations' weapons ban during a meeting with Russian Foreign Minister Sergei Lavrov.

A group of Calgary imams is marking the first line of defense at the foot of the Rocky Mountains against the Islamic State group's recruitment of Canadians as fighters.

Several imams issued a religious edict against IS jihadists last month, denouncing its threats against Canada and its online recruitment after dozens of Canadians -- mostly from Calgary -- traveled to Syria to join their cause.

Amnesty International accused the EU of putting thousands of migrants at risk Wednesday by scrapping rescue operations in the Mediterranean as Italian coastguards said no more survivors have been found from a shipwreck which may have claimed 400 lives.

The rights group accused Europe of "turning its back on its responsibilities and clearly threatening thousands of lives" by forcing Italy to abandon its Mare Nostrum rescue mission last year in favor of the surveillance patrols currently being carried out by its borders agency Frontex.