U.S. Defense Secretary Mark Esper reviews the guard of honour with Vietnam's Defence Minister General Ngo Xuan Lich in Hanoi, Vietnam November 20, 2019. REUTERS/Kham

HANOI (Reuters) - The United States announced on Wednesday it will provide Vietnam with another coast guard cutter for its growing fleet of ships, boosting Hanoi’s ability to patrol the South China Sea amid tensions with China.

U.S. Defense Secretary Mark Esper disclosed the decision during an address in Vietnam, which has emerged as the most vocal opponent in Asia of China’s territorial claims in the South China Sea.

In the same speech, Esper sharply criticized China.

“China’s unilateral efforts to assert illegitimate maritime claims threaten other nations’ access to vital natural resources, undermine the stability of regional energy markets, and increase the risk of conflict,” Esper told students at the Diplomatic Academy of Vietnam.

Reporting by Phil Stewart; Editing by Andrew Heavens