Ahmet Uzumcu, director general of the Organization for the Prohibition of Chemical Weapons, said parties to the organization need to find a predictable way to get chemical weapons out of Syria.
"While the two shipments (of chemicals) this month represent a start, the need for the process to pick up pace is obvious," he said.
The OPCW adopted a plan in November for the destruction of Syria's chemical weapons stockpiles. By December, the group, which received last year's Nobel Peace Prize, said it destroyed parts of buildings used to manufacture weapons in the city of Homs that were rendered inoperable during previous missions.
Robert Mikulak, U.S. envoy to the OPCW, said in a statement the effort to get chemical agents and weapons precursors out of Syria "has seriously languished and stalled."
He said less than 10 percent of the estimated 530 tons of the most dangerous forms of chemicals have been removed so far from Syria. The so-called Priority One chemicals were to be completely removed from Syria by New Years Eve.
The director general said Syrian authorities have expressed their commitment to the chemical weapons removal program, but had concerns about the current security situation in the country.