BEIRUT — U.N. experts charged with starting the process of verifying and eliminating chemical weapons arrived in Syria on Tuesday for the mission endorsed by the U.N. Security Council.

A convoy of about 20 U.N. vehicles carrying the team arrived in Damascus shortly after 5 p.m., witnesses said, after crossing the border from Lebanon earlier in the day.

The U.N. mission, which Washington and Moscow hammered out after an Aug. 21 chemical weapons attack in Damascus prompted U.S. threats of airstrikes against the Syrian government, is expected to continue until at least mid-2014.

More than 100,000 people have died in Syria's conflict, which began in early 2011 with peaceful demonstrations seeking more democracy but has deteriorated into sectarian civil war.

Alluding to the violence, Syria's foreign minister on Monday compared what he described as an invasion of foreign terrorists across Syria to the Sept. 11, 2001, attacks on the United States. Washington dismissed the remark as offensive and disingenuous.