US troops began arriving in Turkey to man the Patriot missile systems from NATO expected to help the country repel any missile attacks or aircraft from neighboring Syria.
The systems are expected to become operational later this month, The Associated Press reported.
More from GlobalPost: Early reports of chemicals used against Syrian rebels
NATO approved the deployment of the surface-to-air missiles last month on the request of Turkey amid "grave concerns" that Syria could use chemical weapons.
The United States, Germany and the Netherlands have each pledged to send two battery units.
More from GlobalPost: US to send troops, Patriot missiles to Turkey over Syria conflict
US troops and equipment are now streaming into Turkey's southern Incirlik Air Base, the US military said Friday, and 400 more troops and additional equipment will be airlifted there in the coming days, according to BBC News.
Syrian officials have said they would never use chemical weapons on their own people, but the country has stockpiles of rockets capable of carrying chemical warheads.
Iranian Army chief Major General Hassan Firouzabadi said any US military support of the conflict in Syria threatens "world war."
The United Nations recently estimated that more than 60,000 people have been killed since the uprising began nearly two years ago, including nearly 31,000 civilians, NBC News reported.