In statements disseminated on social media, the activists say they were inspired by mass protests in Egypt last month that prompted the army to oust president Mohamed Morsi.

Bahrain's regime on Monday vowed to "forcefully confront" demonstrators and prosecute those responsible for "incitement".

The small Persian Gulf Arab state and Western ally that hosts the US Fifth Fleet has been buffeted by bouts of unrest since February 2011 when an uprising led by members of the Shia majority demanded the Al Khalifa dynasty give up power.

The authorities crushed the revolt but protests and clashes have persisted despite continuing talks between government and opposition.

The protests called for Wednesday are symptomatic of rising tensions in the country. In contrast with previous protests, the pending rallies prompted the government to pass tough new laws banning demonstrations in the capital, Manama.

Bahrain's largest opposition group, the al-Wefaq Society, said it was not planning to officially join protests although it supported the right to peaceful demonstrations.

"From what I have been hearing around, I know that it is going to be a peaceful movement but having said that I also expect clashes between the government forces and the protesters, because they are against all protests and demonstrations," the Wefaq leader, Sheikh Ali Salman, told Reuters.

"I only pray that there are no victims."

Wednesday will be the 42nd anniversary of Bahrain's independence from Britain.

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