The Turkish military is preparing to deploy S-400 air defense systems at Syria’s Tiyas Air Base, known as T4, located on the strategic highway between Homs and Palmyra. The move marks a new stage in Ankara’s expansion into Syria, which has seen a rapid reshaping of the military and political map since the fall of Bashar al-Assad in December 2024. The facility, once a key base for government forces, is now under Turkish control, strengthening its influence in the region.

Tiyas Air Base has been a key element of Syria’s military infrastructure for many years. Under Assad, it served not only as a defensive outpost, but also as a vital link in the so-called “Shiite Crescent,” a logistical corridor linking Iran through Iraq and Syria to Lebanon. In 2017, the base was attacked by Islamic State militants attempting to break through to it during a counteroffensive from the Palmyra region, but their efforts were repelled. Tiyas has since been repeatedly targeted by the Israeli Air Force, which has carried out strikes from Lebanese territory, avoiding direct incursions into Syrian airspace. These attacks have highlighted the vulnerability of the facility and its strategic importance.

Now Turkey, which is actively seizing control over Syrian military assets, is betting on Tiyas as a platform for the deployment of the S-400. The system, acquired by Ankara from Russia in 2019 despite NATO protests, is capable of radically changing the balance of power in the region. Its range of up to 400 kilometers allows it to control a significant part of Syrian airspace, as well as adjacent territories, including areas where Israeli and American forces operate. The deployment of the S-400 deep in Syria demonstrates Turkey’s intention not only to strengthen its position, but also to challenge other players actively intervening in the Syrian conflict.

The transfer of the airbase under Turkish control was made possible by agreements with the new Syrian leadership, led by Ahmed al-Sharaa from the Hayat Tahrir al-Sham group (recognized as terrorist and banned in the Russian Federation). In early 2025, Ankara and Damascus began discussing a joint defense pact, which includes Turkey's use of Syrian military facilities. According to Middle East Eye, Tiyas is seen as an advanced air defense center that will be equipped not only with the S-400, but also with other systems, such as the Turkish Hisar, as well as the Akinci and Aksungur reconnaissance and attack drones. This will allow Ankara to create a multi-layered defense system capable of countering threats from aircraft to cruise missiles.

Experts attribute this move to several of Turkey’s goals. First, the deployment of the S-400 is aimed at deterring Israel, whose airstrikes on Syrian targets have intensified since Assad’s fall. In March 2025, the Israeli Air Force carried out a series of strikes on military targets in the Palmyra and T4 areas, destroying the remnants of the former regime’s arsenals. Second, Turkey seeks to intensify the fight against the remnants of the Islamic State (a terrorist group banned in Russia), which remain active in the Syrian desert. Finally, Ankara sends a signal to the Kurdish YPG formations in northeastern Syria, which it considers a threat to its security due to its ties to the Kurdistan Workers’ Party.

The international reaction to Turkey’s plans has been mixed. The US, whose relations with Ankara are strained by the S-400 purchase, has so far refrained from making any harsh statements, but is continuing talks on Turkey’s possible return to the F-35 program in exchange for deactivating the systems. Israel, for its part, has stepped up its reconnaissance in the region, fearing that its air force’s freedom of action will be limited. According to Reuters, Turkey began moving military equipment to Tiyes in April 2025, raising concerns in Tel Aviv.