About 440,000 Syrians are now trapped in areas besieged by fighting, more than double the total from last month, as the war reaches "breathtaking levels of savagery", U.N. aid chief Valerie Amos said Thursday.

Amos told the U.N. Security Council that Islamic State fighters are laying siege to government-controlled neighborhoods in Deir Ezzor, northeast Syria, adding 228,000 people to the growing list of civilians in need of aid.

Iraqi forces buoyed by the first U.S.-led coalition air strikes on Tikrit made a final push Thursday to flush diehard jihadists out of Saddam Hussein's hometown.

U.S.-led warplanes carried out 17 air strikes against Islamic State jihadists in Tikrit overnight in the first wave of coalition bombing raids in support of an Iraqi government offensive to recapture the town, the U.S. military said Thursday.

U.S. Secretary of State John Kerry Thursday held a conference call with Gulf ministers to discuss the Yemen crisis amid Saudi air strikes on Huthi rebels, a senior U.S. official said.

The top U.S. diplomat "commended the work of the coalition taking military action against the Huthis" and noted Washington's support "including intelligence sharing, targeting assistance, and advisory and logistical support for strikes against Huthi targets," the State Department official said.

The Special Tribunal for Lebanon's Defense team continued on Thursday its cross-examination of head of the Mustaqbal bloc MP Fouad Saniora, with questions focusing on United Nations Security Council resolution 1559 and former Premier Rafik Hariri's ties with ex-President Emile Lahoud.

Saniora said: “Hariri fought hard to ensure that the term of later President Elias Hrawi was extended in 1995 in order to avoid the election of Emile Lahoud as president.”

Islamist fighters have seized 17 checkpoints from Syrian regime forces in clashes around the city of Idlib that have cost at least 68 lives in 48 hours, a monitor said Thursday.

"The government and its supporting forces have lost 17 checkpoints and regime locations to the Al-Nusra Front and other Islamist groups in and around Idlib" in the country's northwest, said the Syrian Observatory for Human Rights. 

Britain will begin training Syrian "moderate opposition forces" in Turkey and other regional countries within weeks as part of its efforts to fight Islamic State militants, Defense Secretary Michael Fallon announced on Thursday.

"Defeating ISIL ultimately lies with local forces and we are helping to create effective ground forces in Syria, as well as in Iraq, so they can take the fight to ISIL," Fallon said, using one of the acronyms used to refer to the IS group.

Saudi-led strikes on Yemeni rebels are set to dominate an Arab summit that will consider forming a joint military force as several countries in the region teeter on the brink of collapse.

For years Arab states had contented themselves with directing proxies in regional struggles.

Free Patriotic Movement chief MP Michel Aoun urged on Thursday the minimum amount of unity among the Lebanese to face the upcoming challenges, expressing belief that he is the only one capable of talking to all the rivals and restoring stability in the country.

“If the region reached a balanced state, then all the countries will benefit from it,” Aoun said in a lengthy interview with the pan-Arab daily al-Hayat.

The number of asylum-seekers in industrialized countries rose by nearly half last year, driven by the devastating conflicts in Syria and Iraq, with Germany the top destination, the U.N. refugee agency said Thursday.

In 2014, some 866,000 people applied for asylum in such countries, marking a 45-percent jump from a year earlier and a 22-year high, the U.N. refugee agency said.

Morocco, on guard against attacks like the Tunis museum massacre, prides itself on being a bastion against Islamist extremism with its anti-jihadist "FBI" and training of imams to preach tolerance.

More than 130 "terrorist cells" have been dismantled, 2,720 suspects arrested and 276 plots foiled since 2002, according to Abdelhak Khiame, director of the newly established Central Bureau of Judicial Investigations.