The United Nations Security Council scheduled an emergency meeting Sunday as violence escalated in Yemen, and U.S. troops were evacuated from an airbase, the Associated Press reported Saturday. The meeting will take place amid a rise hostilities after suicide bombers attacked Shiite mosques in Yemen's capital Friday, killing at least 137 people.

Around 100 U.S. Special Operations forces were evacuated from al-Anad airbase in southern Yemen Saturday after al Qaeda seized a nearby town, CNN reported citing unnamed officials. The threat of civil war in the region has grown since Shiite rebels, known as the Houthis, seized Sanaa last year.

Yemeni President Abd-Rabbu Mansour Hadi Saturday called for an "urgent intervention in all available means to stop this aggression that is aimed at undermining the legitimate authority, the fragmentation of Yemen and its peace and stability," he said in a letter to the Security Council, Reuters reported.

"I urge the council to rise up to its responsibilities to protect the security and support the legitimacy in Yemen," Hadi wrote.

The U.N. Security Council condemned suicide bomb attacks in Sanaa Friday after four suicide bombers attacked two mosques during prayers, killing at least 137 people and wounding 357, Reuters reported. 

The Security Council reiterated its determination to combat all forms of terrorism, in accordance with its responsibilities under the Charter of the United Nations. "The members of the Security Council reaffirmed that terrorism in all its forms and manifestations constitutes one of the most serious threats to international peace and security, and that any acts of terrorism are criminal and unjustifiable regardless of their motivation, wherever and whenever, and by whomsoever committed," the U.N. Security Council said in a statement Friday.

The U.N. Security Council scheduled an emergency meeting, beginning at 3 p.m. EDT Sunday, to discuss the Yemen crisis.