WASHINGTON, July 18 (Reuters) - The United States opened an embassy in the Pacific island nation of Vanuatu on Thursday, the latest U.S. move in a long-running competition with China for influence in the Asia Pacific region.

"The opening of the embassy builds upon our efforts to provide more diplomatic presence throughout the region and to engage further with our Pacific neighbors," the U.S. Department of State said in a statement.

The U.S. earlier opened embassies in two other island nations, Solomon Islands and Tonga, and plans to open one more in Kiribati, a State Department official told the U.S. Congress in March. The Kiribati mission is awaiting parliamentary approval, the official said.

Washington has been working to boost its diplomatic presence in the Pacific to counter what it sees as a growing threat from China, its main strategic rival.

In February, the United States cautioned Pacific island nations against accepting assistance from Chinese security forces following a Reuters report that Chinese police were working in Kiribati, a remote atoll nation near Hawaii.

Chinese police have deployed in the Solomon Islands since 2022 after a secret security pact criticized by the United States and Australia as undermining regional stability. Concerns have been raised also over workers in military uniforms in Vanuatu after a Chinese company began logging there.