Nguyen Van Ly is continuing to conduct an insane campaign of sabotage, provocation and defiance

Military newspaper

In March, Mr Nguyen gave written testimony at a US government hearing in Washington, and urged the Americans not to ratify a trade pact until human rights in Vietnam improve.

Shortly afterwards he was placed under house arrest and denounced in the state-run media as a "traitor" for urging the US to link improved trade to guarantees of religious freedom.

Vietnam has expressed anger about delays in the US Congress in ratifying the trade pact, which would give the two countries greater access to each others markets.

'Erroneous actions'

In a statement from Paris, the outlawed Unified Buddhist Church of Vietnam said another priest, Thich Quang Do, 73, had been ordered to appear before a people's court in Ho Chi Minh City on Friday to explain recent "erroneous" actions.

Officials accuse Mr Nguyen of threatening public security

At the time of the house arrest order in March, official media called for Mr Nguyen to be put on trial and punished severely for his defiance of the communist authorities.

An armed forces newspaper said he should be "punished severely by the courts" for his persistent defiance of the regime."

The propaganda charges Mr Nguyen faces carry penalties of 10 to 12 years in prison.

A longtime critic of the government, he has previously spent nearly 10 years in prison and was on Amnesty International's list of prisoners of conscience.

Strained relations

The arrest and news of the summons coincided with a visit by US Assistant Secretary of State James Kelly, the first senior official of the new American administration to visit Vietnam.

Relations between Vietnam and the US have recently been strained, with Hanoi accusing Washington of interfering in its domestic affairs.

The US recently granted asylum to 24 Vietnamese refugees from an army crackdown on unrest in the highlands.