American aircraft carrier Harry S. Truman is in the northern Aegean this week, in part to ensure he can conduct air operations from there if tensions in the region escalate over Russia’s invasion of Ukraine, a US official familiar with the vessel’s current mission has said.

The official did not reveal the exact location of the ship, but said it was not routine to operate in the northernmost waters of the Aegean Sea. The area is relatively limited for carrier operations due to the number of small islands and heavy commercial maritime traffic, reports CNN.

“In the event of further escalation”, the navy could be told to design more airborne patrol fighter jets in the Black Sea, the official said. “If Russia tries to control the Turkish Strait and Turkey seeks NATO support”, the aircraft carrier could be used for combat air patrols over the Black Sea and Dardanelles, according to the official.

Truman fighter jets are currently flying over Romania as part of a NATO mission to demonstrate a presence and determination against Russian aggression.

The carrier is accompanied by the cruiser USS San Jacinto in the North Aegean. Five other US warships and a Norwegian surface warship are further south in the Aegean Sea.