Officials from defense said Tuesday that the USS Harry S. Truman’s schedule and five American warships accompanying her changed to reflect the need for a permanent presence in Europe. The official spoke under anonymity to discuss details of military deployment.

The U.S. and its allies in the West have observed as Russian troops near the border grew to an estimated 100,000. This raised fears that Moscow was planning to invade Ukraine.

Russia annexed Ukraine’s Crimean Peninsula in 2014. It then supported a separatist rebellion in its east. Over the past seven years, more than 14,000 people have been killed and the industrial heartland of Ukraine, known as Donbas, has been destroyed.

Russia denies any intention to launch a new invasion. Instead, it accuses Ukraine of plotting to use force to seize control of territories held by Moscow-backed rebels. This claim has been rejected by Ukraine.

Five U.S. ships make up the Truman strike group: the cruiser USS San Jacinto, the guided missile destroyers USS Cole and USS Bainbridge, USS Gravely, USS Gravely, and USS Jason Dunham. The Royal Norwegian Navy frigate HNoMS Fridtjof Nansen is also included.

On Dec. 1, Truman left Norfolk, Virginia and entered the Mediterranean Sea. It was originally scheduled to continue into the Gulf region.