Bahraini security forces have been accused of using violence to halt an attempt by pro-reform protesters to stage new demonstrations, even as a state of emergency was lifted.
The crackdown came one day after King Hamad had called for a national dialogue, and followed appeals for the authorities in the Gulf state to allow people to demonstrate peacefully.
"People are trying to gather... and they are attacking them," one activist told AFP by telephone, referring to protests in villages around the capital Manama including Diraz, Bani Jamrah and Karzakan.
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"They have already started using birdshot (and) tear gas" against the demonstrators, she said, adding that an unknown number of people had suffered injuries.
Another activist reported a heavy security presence in Bani Jamrah and said security forces had fired tear gas at protesters who dared to venture into the centre of the village.
He added that about 30 women had gathered in front of his house, but security forces used batons and tear gas to disperse them.
A clip on video-sharing website YouTube titled "Riot police attacking peaceful protesters June 1st in Bani Jamrah" showed a small group of young men gathering, some with Bahraini flags, chanting "peacefully, peacefully."
Police then appeared to fire tear gas at them.
The authenticity of the video could be independently verified.
The protests came as Bahrain lifted a state of emergency that was enacted on March 15 amid a bloody crackdown on Shiite-led protests in the Sunni-ruled, Shiite-majority kingdom, which activists had been holding since February 14.
Authorities said 24 people, including four policemen, were killed in the unrest.
Under the state of emergency, security forces cracked down on Shiite villages, arresting hundreds of people, many of whom have been referred to special courts.
Activists had called for the protests on the "February 14 Revolution Youth Coalition" page of Facebook.
The protests were to "confirm that our revolution has not and will not end until our people... take their right... of self-determination," it said, referring to Sunnis and Shiites.
Rights group Amnesty International had called on the authorities to allow the protests to go ahead.
"Bahraini authorities must not make the same mistakes as in February and March, when largely peaceful protests were violently suppressed by government security forces," said Malcolm Smart, Amnesty's Middle East and North Africa director.
"As the state of emergency is lifted, the authorities must allow people to peacefully exercise their rights to freedom of expression and association," Smart said.
On Tuesday, King Hamad had called for national dialogue beginning in July.
He appealed for "all necessary steps to prepare for a serious dialogue, comprehensive and without preconditions, adding that it should "start from July 1."
After the protests began in February, the king charged Crown Prince Salman with opening a national dialogue, a call that was dismissed by the opposition until various preconditions were met.
"Today marks the final day of the State of National Safety (state of emergency) in Bahrain and the military forces have begun their withdrawal from the streets," Prince Salman was on Tuesday quoted in a government statement as saying.
"As a nation, we face several challenges ahead as we seek to address issues of concern, while continuing efforts to prevent extremism and sectarianism taking hold in Bahrain."
But the prospects for dialogue were called into question by the reported interrogation of opposition leaders on Tuesday.
Al-Wefaq, the main Bahraini Shiite opposition group, said in a Wednesday statement that its head and three more of its high-ranking officials had been interrogated by a military prosecutor the day before.
In the statement, Al-Wefaq said that Sheikh Ali Salman, Ibrahim al-Marzouk, Abdel Jalil Ali Ibrahim and Mohammed Yussef al-Mazaal had been interrogated for five hours on Tuesday.
