NICOSIA — Amnesty International said on Wednesday it had evidence Iranian security personnel used "unlawful force" over the weekend during peaceful protests after Tehran admitted it accidentally shot down a Ukrainian airliner.

The rights group cited verified images and eyewitness testimonies indicating authorities had targeted protesters with rubber bullets, tear gas and pepper spray, along with pointed airgun pellets normally used for hunting.

It said security forces also beat demonstrators with batons, kicked and punched them and made arbitrary arrests during protests on Saturday and Sunday.

A Ukraine International Airlines plane was shot down by a missile shortly after takeoff from Tehran on Jan. 8, killing all 176 passengers and crew on board.

Iran initially dismissed Western claims it was brought down by a missile before admitting it on Saturday.

The blunder and the official response sparked four consecutive nights of protests.

Amnesty cited verified videos in which people helping the wounded are heard saying they had been shot, as well as X-rays showing pellets lodged in two protesters' legs.

It added that the Iranian security and intelligence forces were "maintaining a heavy presence in some hospitals raising fears they plan to arrest patients".

The London-based rights group said that "in many cases the actions by the security forces violated the absolute prohibition of torture and other ill-treatment under international law".

Several protesters had not sought hospital treatment for pellet wounds for fear of being detained, it added, while some facilities in Tehran had turned away the wounded, warning they could be arrested.

Amnesty cited an eyewitness identified as Mahsa from Tehran, who said security forces had fired tear gas into the entrance of a metro station to stop people joining the protest.

"A member of the security forces chased me when they saw me filming the protest and that's when I was shot in the leg with a pointed pellet," the statement quoted her as saying.

She said the authorities had threatened doctors and that several centers where she had sought treatment had turned her away.

Amnesty also cited reports of scores of arrests in cities where demonstrations took place, saying authorities were "denying the families of some detainees information about their fate and whereabouts".

Philip Luther, Amnesty's regional research and advocacy chief, urged Iran to release those who had been arbitrarily detained.

"The Iranian authorities must end the repression as a matter of urgency and ensure the security forces exercise maximum restraint and respect protesters' rights to peaceful expression and assembly," he said. — AFP