WASHINGTON — The United States and its partners are planning a series of rapid steps to dismantle Syria’s chemical weapons program, a strategy that is intended to guard against backsliding by President Bashar al-Assad and limit the time that international experts need to work in the country, according to senior American officials.

A major step is to be taken in early November, when equipment for producing chemicals and filling warheads and bombs with poison gas is to be destroyed by the Syrians under international supervision. That move can be carried out by equipment as simple as sledgehammers and bulldozers.

International monitors began the process of destroying that equipment on Sunday. “Missile warheads, aerial bombs and mobile and static mixing and filling units were destroyed and disabled in a number of different ways, including with cutting torches,” said a member of the joint team of experts from the Organization for the Prohibition of Chemical Weapons and the United Nations, speaking in Damascus on the condition of anonymity according to the team’s policy. “The plan is to do more such destruction and disabling in the coming days.”

But a major centerpiece of the disarmament effort will be a mobile and highly sophisticated system developed by the Pentagon that will probably be set up outside Syria to neutralize large quantities of chemicals transported out of the country.