WASHINGTON - The Obama administration is providing an additional $100 million for humanitarian aid for displaced Syrians, officials said Wednesday, bringing to $510 million the total U.S. aid commitment since the civil war began more than two years ago.

The new aid, which Secretary of State John Kerry will announce Thursday during a visit to Rome, will help support 1.4 million civilians trapped by violence within Syria's borders, as well as refugees who have fled to camps in neighboring Jordan, Lebanon and Turkey, they said.

The officials requested anonymity because the aid had not been officially announced.

The decision is not linked to White House deliberations over whether the United States should provide weapons and ammunition to rebels fighting the government of President Bashar al-Assad or to growing suspicions that Syrian forces used chemical weapons.

The administration provides some nonlethal aid to the rebels, such as communications equipment, military-style rations and bandages. But U.S. officials fear that arming the insurgents could wind up strengthening extremist militias, including factions linked to al-Qaeda.

The additional aid will help the Obama administration deflect criticism that it is not doing enough to deal with a conflict that has killed nearly 80,000 Syrians and threatens to engulf the broader Mideast.

The money will be administered by U.N. agencies to help provide food, shelter, and health care at refugee camps. The aid also will include some cash payments to civilians in Syria. The United States is the largest donor of humanitarian relief for Syrians.