HANOI – A Vietnamese activist says he was stopped by authorities from meeting U.S. President Barack Obama in Hanoi with other civil society figures.

Nguyen Quang A said he was taken by a group of police officers from his home early on Tuesday and forced into a car. He claimed that he was then driven out of the capital and kept away for more than five hours.

During this time, Obama met six civil society leaders and later said several people had been prevented from meeting him.

The U.S. leader said that despite great strides made by Vietnam, Washington had concerns about the limits it puts on political freedom. He praised those Vietnamese who were “willing to make their voices heard”.

On Monday, Obama announced he was scrapping a Cold War-era ban on weapons sales to Vietnam, as ties between the former foes grow closer thanks to trade and mutual fears of Chinese expansion in disputed seas.

The visit is Obama’s first to the country – and the third by a sitting president since the end of the Vietnam War in 1975. Direct U.S. involvement in the conflict ended in 1973.

– with other agencies