U.S. President Barack Obama announced on Monday during his first visit to Vietnam that Washington will fully lift a half-century-old embargo on sales of lethal arms to the communist country, underlining warming relations between the former foes amid rising tensions with Beijing over the South China Sea.

At a lavish state luncheon in Hanoi, Vietnamese President Tran Dai Quang toasted Obama’s first visit to the country as the arrival of a warm spring after a cold winter.

Obama, the third U.S. president to visit Vietnam since ties were restored in 1995, has put a strategic ‘rebalance’ towards Asia-Pacific at the heart of his foreign policy.

Vietnam, where the United States was at war until 1975, has become a critical part of that strategy amid concerns about China’s growing military might and its sovereignty claims in the South China Sea.

… While Vietnam has recently obtained submarines equipped with land-attack missiles, advanced air defense radars and state-of-the-art jet fighters from other nations, it was likely to seek advanced surveillance and intelligence systems from the United States, said Collin Koh, a military expert at Singapore’s S. Rajaratnam School of International Studies.