HANOI, VIETNAM — U.S. weapons manufacturers could work with Vietnamese counterparts to help build Vietnam’s armed forces, the U.S. ambassador to the southeast Asian country said on Thursday. “Our goal is to ensure that Vietnam has what it needs to defend its interests at sea, in the air, on the ground and in cyberspace,” U.S. Ambassador Marc Knapper said at an international arms expo in the Vietnamese capital, Hanoi. The expo, held at the Gia Lam airport, brought together 250 exhibitors, including geopolitical rivals such as the United States, China, Russia, Ukraine, Israel and Iran. U.S. exhibitors included Boeing and Textron Aviation. China was present with Norinco and Gaodu International Trade. Iran’s defense ministry pavilion wasn’t far from booths set up by Israeli companies Rafael Advanced Defense Systems and Israel Aerospace Industries. Several Russian firms also attended, along with Ukraine’s Motor Sich. Vietnam has been trying to increase its domestic arms manufacturing while reducing its reliance on Russia for weapon imports. In 2022, Russia made up around 60% of all of Vietnam’s military purchases, according to the Stockholm International Peace Research Institute. But Vietnam’s longstanding efforts to diversify its imports have been accelerated by the war in Ukraine. It has also been trying to boost its own capacity to make arms and displayed military equipment it made at the expo. A key driver for Vietnam is the escalating tensions in the South China Sea, a key trade and security route. It is a flashpoint in Asia and a fault line in the U.S.-China regional rivalry. Vietnam has been critical of China’s increasingly hostile actions in the disputed waters. Vietnam and other Southeast Asian countries have overlapping claims in the busy sea passage. Vietnamese Prime Minister Pham Minh Chinh hailed the event as a “message of peace, cooperation and development.” He was later given a tour of a military plane made by U.S. firm Lockheed Martin.