Footage has emerged of the moment a protester "thought he would be killed" by staff at the Bahraini embassy in London as he was allegedly struck while he sat on the edge of the roof.
Moosa Mohammed, 38, had climbed on to the roof to protest about the imminent execution of two men in the Gulf state.
The footage apparently shows a plank-wielding figure hitting the activist while he sits in a precarious position.
The embassy said staff stepped in for the demonstrator's safety.
Mr Mohammed said he decided to climb on to the roof of the building in Knightsbridge to step up his protest as no apparent progress was being made to help alleged torture victims Ali Mohamed Hakeem al-Arab and Ahmed Isa Ahmed Isa al-Malali. The two were executed by firing squad on 27 July, the day after the alleged assault on Mr Mohammed.
According to Bahraini citizen Mr Mohammed, three staff members arrived on the roof to apprehend him.
The video, released by the Bahrain Institute for Rights and Democracy, shows one person hitting Mr Mohammed with what the activist described as a metre-long piece of wood.
"This staffer beat me with the weapon, pushing me towards the edge," Mr Mohammed said.
"He told me that 'we have two people being executed in Bahrain and you will be the third'. I was frightened for my life."
Police officers outside the embassy called on the embassy staff to "get back inside", at which point Mr Mohammed said they dragged him towards a nearby stairwell.
Police said officers were called to the embassy to reports of a man on the roof. They said they entered the building and detained Mr Mohammed on suspicion of trespass on a diplomatic premises. The embassy's security staff were also present.
Had the police failed to intervene, "I truly believe they would have killed me," said Mr Mohammed, who has been bailed to a date later in the month.
The embassy said in a statement the dissident was "threatening to jump off" and was restrained "for his own safety until police arrived".
It also told the Guardian the allegation that "embassy staff were trying to kill Mr Mohammed is completely unfounded and ridiculous" and accused him of "unlawfully trespassing".