An American student held in Vietnam for "causing public disorder" at violent protests this month has appeared on state television to say he regrets breaking the law and will stay away from future rallies.
William Nguyen was detained on June 10 in Ho Chi Minh City after attending mass demonstrations against proposed special economic zones that would grant investors 99-year leases.
Video footage shows the Texas-born 32-year-old with a bleeding head wound being dragged by plainclothes men through the streets before being taken into custody.
Police have launched an investigation into Nguyen for "causing public disorder" and have accused him of trying to damage a fence and flip over police vehicles on the main road to the airport.
Nguyen, a Yale graduate, appeared on television on Monday night to say he broke the law.
"I understand that my acts violated (the law)... I regret that I caused trouble for people heading to the airport. I blocked traffic and caused trouble to my family and friends," Nguyen said in Vietnamese on HTV in footage provided by city police.
"I will not join any anti-state activities any more," added Nguyen, who was arrested while passing through Vietnam en route to Singapore where he was set to receive a master's degree next month.
Major protests in several cities turned violent in some places and scores were detained after the gatherings, rare in the one-party state where demonstrations are routinely banned or broken up.
Nguyen tweeted from the rallies, posting images of large crowds and saying he supported Vietnamese people "exercising their civic duty to protest injustice".
Friends and family lobbying lawmakers in Washington for Nguyen's release say he did not have a political agenda.
At least 30 people are still in custody and security forces blanketed Ho Chi Minh City last weekend to deter further protests.
Demonstrators have rallied against a draft law to grant lengthy leases in proposed special economic zones, citing fears valuable land would be handed over to China.
The bill made no specific mention of China and the government has said it would consider shorter leases, but the concession did little to assuage anger.
Prime Minister Nguyen Xuan Phuc said the government would consider public feedback but issued a warning to protesters.
"If you oppose officials on duty, vandalise state property... then you have to be strictly handled in accordance with the law," Phuc said Monday.
China and Vietnam have had a fraught relationship since a brief but bloody border war in 1979 and resentment over Beijing's extensive claims in the South China Sea runs high in Vietnam.
The long-simmering dispute boiled over in 2014 when Beijing moved an oil rig into waters claimed by Vietnam, prompting protests across the country that left several Chinese nationals dead.