Hanoi - The US Embassy in Hanoi expressed 'concern' Thursday over the arrests and convictions this week of several labour activists and bloggers, as well as a group of Catholics involved in a clash with police in May.

The statement said the arrests and trials 'contradict Vietnam's own commitment to internationally accepted standards of human rights.'

The criticism came as US Secretary of State Hillary Rodham Clinton prepared to visit Hanoi on Saturday for an Asian summit meeting.

On Wednesday, a court in Ho Chi Minh City sentenced three independent labour activists to up to nine years in jail for organizing strikes and handing out leaflets criticizing the government.

Also Wednesday, six Catholic parishioners from a village in central Vietnam were convicted of causing public disorder. The parishioners were among hundreds who clashed with police when they tried to hold a funeral in a Catholic cemetery that local authorities had shut to build a tourism resort.

Two of the parishioners received sentences of nine months to a year, while the rest were given suspended sentences. Villagers' relatives this summer told the US Congress that police had beaten at least one villager to death.

A lawyer for the parishioners, Cu Huy Ha Vu, said the court in the city of Danang had refused to let him defend his clients, saying his documents were not in order.

'This is a form of discrimination against Catholics,' Vu said.

Earlier this week, police arrested society blogger Le Nguyen Huong Tra, after she alleged a senior police official had granted favours to singers and actresses romantically linked to his son.

Political blogger Phan Thanh Hai was arrested Monday, and authorities have refused to release Nguyen Van Hai, another political blogger sentenced to 30 months in prison for tax evasion, after his sentence ended October 20.

In letters sent this week, US Senator Barbara Boxer and four members of the US House of Representatives urged Clinton to take up human rights issues when she attends the East Asia Summit in Hanoi on Saturday.

The US and Vietnam have grown closer in recent months over shared concerns about rising Chinese power. In a visit to an earlier summit in Hanoi in July, Clinton expressed US support for Vietnam's approach to resolving maritime territorial disputes with China, a hot-button issue that has preoccupied the region over the past year.