ANTAKYA, Turkey — The Turkish military sent troops, armored personnel carriers and missile batteries to the Syrian border on Monday, shoring up defenses against a country that has plunged into turmoil with some serious potential repercussions for Turkey.

In the past few weeks, as Syria’s government has struggled against an inchoate but spirited rebel army, chunks of Syria have fallen into the hands of Kurdish militias, while at least one area along Turkey’s border is now controlled by jihadist groups dominated by heavily armed foreign fighters.

Television pictures on Monday showed a convoy of Turkish army trucks chugging down a highway running along the Syrian border. The semiofficial Anatolia News Agency reported that mobile missile batteries in Iskenderun, a southern coastal town, were being relocated by rail to Islahiye township, along the border.

Turkish officials were quick to describe the border buildup as “routine,” but at the same time, one government official said, “It is not possible to expect Turkey to act as if nothing is happening.”