A protester who was struck in the head by a tear gas canister fired by police in Bahrain last week has died, opposition officials say.
Mahmood Aljazeeri, 20, died in hospital on Thursday, seven days after being injured, according to a statement released by the Al Wefaq society.
Mr Aljazeeri is the third person to be killed during anti-government protests in Bahrain in the past week.
Violence flared during demonstrations marking two years of protests.
Another member of Mr Aljazeeri's family was shot and killed by police, and a police officer died after being attacked, during unrest on 14 February, the anniversary of the occupation of Pearl Roundabout in the capital Manama by pro-democracy activists.
Mr Aljazeeri was wounded in his home village of Nabi Saleh.
His relative, Hussain Aljazeeri, 16, was killed after being struck in the abdomen with birdshot pellets fired at close range on the same day.
Police officer Mohammed Asif died after being hit by what was described as a projectile hurled at him by rioters.
Al Wefaq has released what it says is video footage of the incident involving Mahmood Aljazeeri. It shows him bending down to pick up a missile to throw at a line of police approximately 12 metres (40ft) away.
He then collapses after being hit by a canister fired from the police line. Other demonstrators are seen rushing forward to carry him away.
Opposition activists have often stated that police in Bahrain use tear gas guns inappropriately, firing directly at protesters rather than arcing the canisters so as to avoid serious injuries.
Al Wefaq says that Mr Aljazeeri is the fifth person to have died after being struck by a tear gas canister. More than a dozen have suffered serious eye and head injuries since the unrest began.
Former Miami police chief John Timoney was hired by the Bahraini government two years ago to improve policing methods. When asked last year about the rules of engagement for tear gas, he told the BBC that police in America are trained not to fire head-high and to either arc the canister into the air or roll it on the ground.
He said that the purpose for using tear gas in Bahrain is to keep the protesters at a distance and added "the police do not purposefully hit people with it".
Mr Timoney said that a tear gas canister could be a lethal weapon but it was not intended to be used that way.
Regarding the death of Hussain Aljazeeri the Chief of Public Security Maj-Gen Tariq Hassan al-Hassan issued a statement saying that police had come under attack from rioters "with rocks, steel rods and Molotov cocktails.
Warning shots were fired but failed to disperse the advancing crowd who continued their attack. Officers discharged birdshot to defend themselves".
According to the general, it was at that point "at least one protester was injured" and subsequently died of his wounds at the country's main hospital, the Salmaniya Medical Complex.
However a photograph released by Al Wefaq and seen by the BBC appears to cast doubt on that version.
In the photograph a man said to be Hussain Aljazeeri is seen just after being hit by the birdshot. Two or three other protesters are seen running towards him from an alleyway. The officer who shot him is seen at the corner of a building, firing at a distance of not more than 10 metres.
On 14 February 2011, peaceful protesters took over an iconic Bahraini monument, Pearl Roundabout. Three days later security forces cleared the site using tear gas, batons and birdshot.
At least two protesters died and hundreds were injured.
As violence escalated 35 people, including five police officers, were killed, hundreds more were hurt and thousands jailed in February and March 2011.
The vast majority were Shia Muslims in a country ruled by a minority Sunni royal family.
Since then, opposition and human rights activists say nearly 50 people have been killed, a figure which the government disputes.