Bahraini protesters battled with riot police near Manama on Friday after the funeral of a woman whose family said she died after tear gas entered her home twice in the past week.
A UN rights body this week expressed concern over the use of excessive force and tear gas by Bahraini security forces.
Police moved in with water cannon and armoured vehicles to break up hundreds of protesters as they approached a checkpoint near 'Pearl Roundabout', hub of pro-democracy protests last year led by majority Shi'ite Muslims complaining of marginalisation.
The wind carried some of the tear gas away, allowing youths to lob petrol bombs at close range at the vehicles, scoring direct hits. The water cannon fired hot water during the clashes in the district of Jidhafs on the edge of the capital.
The protesters carried banners in the name of the February 14 Youth Coalition, a movement formed since last year's uprising which says it wants the overthrow of the Al Khalifa family that dominates Bahrain's government and economy.
Police later brought in reinforcements of at least several hundred riot police with batons and shields who fired tear gas into the neighbourhood as youths taunted them from a distance, sometimes grabbing the tear gas canisters and hurling them back.
"Come and fight hand to hand, you cowards, you animals!" one teenager shouted before throwing a rock at police, a mainly Sunni force which employs many foreigners.
Police fired back, engulfing a vegetable market in tear gas.
Earlier, residents buried the body of 59-year-old Abda Ali AbdulHussein who died overnight after her home was tear gassed, her son Ali said at the graveyard.
"I consider her a victim of the clashes," he said, adding she had been discharged from hospital this week still suffering lung inflammation after tear gas entered her home a week ago.
"She collapsed in the bathroom. We called a military hospital nearby for an ambulance but they didn't have any free. By the time one came from the main public hospital she had died," he said, adding that his mother had been diabetic.
The UN High Commission for Human Rights said this week it wanted to investigate possible disproportionate use of force against demonstrators in Bahrain, citing excessive use of tear gas and a rising death toll.
Activists say at least 33 people have died since June amid daily clashes in Shi'ite districts, as the government tries to lock protesters in to stop any renewed mass movement in Manama.
Police question the causes of death and their attribution to the political conflict. They say they are showing restraint in the face of violent youth challenging state authority.
Friday's clashes erupted during a series of 10 licenced protests organised by the Gulf Arab state's official opposition parties, led by the Shi'ite Wefaq group.
There were clashes at some other protests, and youths pulled down a lampost thought to carry a security camera facing a popular coffee shop in the Budaiya district. A police statement said Wefaq leaders would be questioned over the incidents.
The Feb. 14 Youth Coalition protesters broke away from one of those official protests, ignoring Wefaq organisers in orange vests with Wefaq logos who were directing traffic.
"This protest is for bringing down the regime. This one's for fighting," said one man as he ran down the street to join the group marching towards Pearl Roundabout, which has been under heavy guard and closed to traffic for a year.
Opposition parties, which include some Sunni and secular groups, want to reduce the powers of the Sunni ruling family, give parliament legislative clout and form a new cabinet. The government has been headed by King Hamad's uncle Sheikh Khalifa since Bahrain became independent in 1971.
A senior ruling family member has been in contact with Wefaq over possible dialogue to end a crisis that has slowed the economy. Hotels and some office blocks stand half-empty. Manama is no longer the weekend getaway it once was for Saudi tourists.
"The people of Bahrain announce that they will continue to use street action everywhere as long as we do not have our rights and one authority monopolises administration of the country," Wefaq and three other parties said in a statement.
Bahrain is aligned with Washington in its conflict with Iran over its nuclear work and hosts the US Navy's Fifth Fleet.
The United States has urged Bahrain to begin dialogue to end the crisis but Manama must also heed Saudi Arabia, with which it shares a major oil field.
Riyadh sent troops last March to help Bahrain break the protest movement, which erupted after revolts in Egypt and Tunisia shook the region by removing long-entrenched rulers.
Diplomats and opposition figures say Saudi Arabia is now worried that the turmoil in Bahrain could distract attention from its efforts to support rebels in Syria and could inspire Shi'ites in its Eastern Province to challenge the state.
Some Sunni groups in Bahrain do not want the government to give in to the Shi'ite-led opposition, which they accuse of seeking to use street violence to take power.
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