JERUSALEM — U.S. Secretary of State John Kerry is sending a strong warning to Syria, saying that “the threat of force is real” if it does not carry out a plan to hand over its chemical weapons.

Kerry issued the warning during a stop in Jerusalem on Sunday, where he discussed the new U.S.-Russian plan to rid Syria of its chemical weapons by the middle of next year.

Kerry stressed that it would be crucial for Syria to honor the agreement. Otherwise, the U.S. threat to use military force against Syria remains in effect.

Kerry said: “We cannot have hollow words.”