The U.S. military began deploying troops and equipment in Turkey on Friday, as part of its support of NATO's Patriot missile batteries being set up along the border with Syria.

Over the next several days, the United States will deploy 400 U.S. personnel from an air defense battalion based in Oklahoma, the U.S. European Command (EUCOM) in Stuttgart, Germany, said. About 400 of the troops will fly into Turkey on U.S. military aircraft, while additional equipment will arrive by sea later this month, it added.

The group that arrived Friday was made up of 27 U.S. troops who landed in Gaziantep, Turkey, according to Turkish state news agency Anadolu, quoted by CNN.

U.S. State Department spokeswoman Victoria Nuland described them as "a site survey team." Pieces have to be brought in and assembled in a phased deployment, she explained.

The deployment of six Patriot batteries, including two from Germany and another two from the Netherlands, came in response to Turkey's request to NATO, who plans to protect the country from any spread of the Syrian conflict. The forces will augment Turkey's air defense capabilities, EUCOM said.

NATO Secretary General Anders Fogh Rasmussen said in mid-December the Syrian regime was using "Scud-type" missiles (short-range ballistic missiles). Some of these missiles were launched near the Turkish border.

"Turkey is an important NATO ally and we welcome the opportunity to support the Turkish government's request in accordance with the NATO standing defense plan," said Navy Vice Admiral Charles Martoglio, U.S. European Command deputy commander.

The Patriot batteries will fall under NATO command when set up is complete and the systems are operational in the next several weeks, Martoglio said. The deployment will be defensive only and will not support a no-fly zone.

The duration of the deployment will be determined by the United States, Germany and the Netherlands in coordination with Turkey and NATO.

"They'll obviously stay as long as NATO nations and Turkey think is necessary against the scenario that we face," Nuland said.