Bahrain expelled two American rights activists on Saturday after police used teargas and stun grenades to break up a protest on Saturday that tried to march towards the roundabout at the centre of a failed pro-democracy uprising last year.
The activists had come as part of a group called Witness Bahrain which says it wants to observe events on the eve of the 14 February anniversary of protests led mainly by the Shiite majority for democratic reforms in the Gulf Arab state.
"Huwaida Arraf and Radhika Sainath arrived in Bahrain in the last few days and obtained tourist visas upon arrival at the airport," a statement from the government's Information Affairs Authority said.
"However, once in Bahrain, they declared their intentions to join demonstrations in order to report on them. Arraf and Sainath were picked up at an illegal demonstration in Manama this afternoon."
It said they had already been deported but associates said they had not yet left the country.
A statement by Witness Bahrain said the women, human rights lawyers, were taking part in a peaceful demonstration.
"The two women are part of the Witness Bahrain initiative, which arrived in Bahrain in response to a call by Bahraini democracy activists for international observers," it said. "Huwaida was dragged away by numerous security forces after sitting on the ground."
Some rights activists were denied entry to Bahrain last month and a member of the team from Japan's NHK television said on Saturday they had been prevented from entry at Manama airport. Officials were not available for comment.
The government said last week it denied visas to some journalists because of an overflow of visa requests.
Egypt's military rulers have began legal action against Americans and Egyptians for activities with non-government organisations that they say was not legal or authorised.
Two groups of several hundred activists gathered at different points in Manama's old market area on Saturday afternoon in an apparent effort to dupe riot police who were scattered through the district, before suddenly marching towards the roundabout, now renamed Al-Farouq Junction.
Security forces maintain a tight guard on the junction, which has remained blocked to traffic, to stop protesters returning.
"To the roundabout, to the roundabout," chanted protesters, led by prominent rights activist Nabil Rajab. Behind them, police using megaphones warned the crowd that the march was unauthorised and they should disperse. Police then fired teargas and stun grenades at the march.
Riot police then seized Arraf, a Palestinian American who campaigns for non-violent protest by Palestinians. It was not clear when Sainath was detained.
Police used stun grenades and teargas after a scuffle between women protesters and police over Arraf's arrest. Police also cornered Rajab to stop the march reforming.
"This proves to everybody that peoples' spirit is still alive and coming back, and we're not going to go away," he said.
Bahrain has been in turmoil since the democracy movement erupted last year, followed by months of violence between riot police and teenagers that has worsened in the past two months.
Bahrain escaped heavy censure from the United States, which regards Bahrain as a key ally in its conflict with Iran. The US Fifth Fleet is based in the island kingdom.
Demonstrations, sometimes organised by leading Shia opposition party Wefaq with government approval, have multiplied as the 14 February anniversary of the uprising approaches.
Youth protesters in Shiite villages have also clashed with security forces, throwing petrol bombs and iron bars and blocking roads with burning tyres.
Activists say at least two people have died in police custody in the past month and others have died from apparent effects of teargas, taking the total dead since Feb. 14, 2011 to over 60. The government disputes the causes of death.
In a sign of the division tearing at Bahraini society, Sunnis organised an alternative rally in Manama.
Gathering at the al-Fateh mosque for a rally led by pro-government cleric Sheikh Abdul-Latif Al Mahmood, they said they were worried the Al-Khalifa family-led government would give in to Wefaq's demands for parliament to form the cabinet.
They said Shias were using violence for political gain.
"We want to send a message to the government that we are against the terrorism and the government should listen to us as well," said a housewife who gave her name as Nour.
"We are afraid. Bahrain was a land of peace, where we didn't lock our doors at night and women would go out without fear of anybody," said Hala Ahmed, a doctor.
They said Sunnis were moving out of some districts because of the continuing clashes between police and youths.
Asked if he could agree with the opposition demand for a Western-style parliamentary democracy, Nader Mohamed said: "In the long run, yes, why not? But not in the current situation."
Bahrain's Sunni rulers have given parliament some more powers of scrutiny over ministers and budgets, but are resisting opposition demands that the elected parliament be given the power to approve cabinet appointments.