Russia’s defense ministry Friday dismissed concerns by the United States over bomber planes refueling at a former American base in Vietnam and the claims that the practice could lead to increased tension in the Asia-Pacific region. The ministry was responding to a U.S. request to Vietnam last week that it stop letting Russia’s nuclear-capable bombers use the base because the planes were conducting “provocative” flights in shows of strength.

“It is strange to hear such statements from representatives of the state whose armed forces are permanently stationed in a number of Asia-Pacific countries and which continues to increase its level of military activity in the region," Russia's defense ministry said, according to Reuters. The ministry added that Russian Air Force activities in Vietnam were "carried out in strict accordance with international norms and bilateral agreements [and] are not directed against anyone whatsoever and shall not be a threat to peace and stability in the Asia-Pacific region.”

The ministry also said the U.S. notion that the refueling of Russian bombers in Vietnam could exacerbate regional tensions was "puzzling."

Russia’s defense ministry said Jan. 4 that its Il-78 tanker aircraft used Cam Ranh Bay, a deepwater harbor in Vietnam, to enable refueling of its TU-95 Bear strategic bombers last year, according to Reuters. Vincent Brooks, commander of the U.S. Army in the Pacific, told Reuters that the nuclear-capable bombers made flights around the U.S. Pacific Ocean territory of Guam. A spokeswoman for the U.S. Embassy in Hanoi, Vietnam, was quoted by the Voice of America radio station Thursday as saying the U.S. request was conveyed last week to the Vietnamese government, which had not yet responded.

Vietnam is torn between its alliances with Russia and the United States. Moscow, a longtime ally, backed Hanoi against the U.S. during the Vietnam War that ended in 1975, but Hanoi has recently sought closer ties with Washington over its concerns about China’s growing power and aggression in the Asia-Pacific region, especially in the South China Sea. Washington, sharing Hanoi's concern about China, has welcomed the U.S.-Vietnam cooperation, and has sought to secure itself greater access to Cam Ranh Bay as part of its strategic "pivot" to Asia, with U.S. ships visiting the bay for repairs in recent years.

Officials at the U.S. Department of State have highlighted Washington's respect for Hanoi’s right to enter into agreements with other countries, and a senior official said Thursday there was not "any indication that the Vietnamese relationship with Russia is meant to reduce, weaken or impact the relationship with the United States,” according to Reuters.