"We have reached an impasse. This government is not serious about having a real dialogue, to listen to the demands of the Bahraini people and implement those demands which cannot be ignored," he said.

In a separate development, Amnesty International on Monday criticized a Bahraini appeals court for delaying until April 30 a hearing for a group of protest leaders sentenced over last year's uprising, including one who has been on a hunger strike for more than two months.

"The Bahrain authorities' delaying tactics are toying with the life of Abdulhadi al-Khawaja, who is on death's doorstep as he enters his 75th day on hunger strike," Hassiba Hadj Sahraoui, an Amnesty regional deputy director, said in a statement.

Sponsors who ploughed money into Formula One have been left squirming after the motor sport's organizers ignored opposition calls to cancel the race.

But Formula One chief Bernie Ecclestone said "there is no such thing as bad publicity", putting a positive spin on the race, which drew widespread condemnation from abroad and became a focus for anti-government protests in the small island kingdom.

Britain's Channel 4 said on its website on Monday that its three-man news team had been deported after being detained on Sunday.

While motor sports journalists were invited to cover the race, reporters from Reuters and some other news organizations who usually write about Middle East politics were denied visas. Channel 4 said its team had been working without accreditation.

"So when we were caught filming a planned demonstration in one of the Shia villages, they have not been particularly pleasant," correspondent Jonathan Miller said in a posting on the website.

(Additional reporting by Rania El Gamal and Andrew Hammond in Dubai; Editing by Andrew Osborn)