The Arab League has indefinitely postponed a meeting on the Syria crisis, suspending the effort to find a replacement for former United Nations envoy Kofi Annan.

Annan resigned after his cease-fire plan, ignored by both sides, collapsed amidst worsening violence. The blueprint sought to fill the void left by the United Nations Security Council, where Russia and China repeatedly have stymied efforts to call for Syrian President Bashar al-Assad's ouster.

The United Nations has so far been limited to an observer mission in Syria, with about 150 personnel stationed there. The U.N. mandate sanctioning the mission is set to expire soon, and Secretary General Ban Ki-moon has called for a "flexible U.N. presence" there that would allow the body to gather facts about the conflict. 

"A continued U.N. presence in Syria that goes beyond our important humanitarian work would allow systematic and meaningful engagement with the Syrian stakeholders, inside the country," Ki-moon wrote in a Friday letter to members of the Security Council.

As diplomatic efforts continue to falter, some countries are seeking ways to assist the Syrian dissidents fighting to topple Assad. United States Secretary of State Hillary Clinton said that the U.S. and Turkey are coordinating on ways to "help the opposition inside Syria," saying the two countries has set up a working group to analyze possible responses like establishing a no-fly zone.

The United States has already helped furnish the Syrian rebels with communication equipment, but activists in the besieged city of Aleppo said on Sunday that all communications lines were down.