The United States has decided to "completely lift" its ban on selling lethal weapons to Vietnam, the two countries' presidents, Barack Obama and Tran Dai Quang announced on Monday. Obama, who is on a landmark three-day visit to the country, landed in Hanoi earlier in the day.

The US, however, has added a rider to the development, with Obama saying the weapons trade will depend on the Southeast Asian country's human rights commitments even after the restrictions are relaxed, reported Reuters.

"Vietnam very much appreciates the US decision to completely lift the ban on lethal weapon sales to Vietnam, which is the clear proof that both countries have completely normalised relations," Quang said during the joint conference.

Obama is the third US president to visit the country since the end of the Vietnam war in 1975.