The United States and Russia have agreed to extend a cessation of hostilities in Syria to include Aleppo Province, site of an uptick in fighting.
In announcing the agreement on May 4, the U.S. State Department also said Moscow and Washington will coordinate to strengthen monitoring of the new arrangement.
It is critical that Russia redoubles efforts to press Syrian President Bashar al-Assad to comply with the new arrangement while Washington does its part with Syrian opposition forces, the State Department said.
Moscow and Washington finalized a nationwide cease-fire in late February, but have struggled to make it stick.
The violence in Syria's largest city and once its key commercial center has continued for almost two weeks despite intense diplomatic efforts to restore the cease-fire.
The UN Security Council also was due to meet later on May 4 to discuss the escalation.
On May 4, three people were killed in renewed shelling by Syrian rebels of government-held areas in Aleppo, state media and opposition activists said.