International governments and human rights groups have expressed concern at the news that Egypt has sentenced to death more than 500 supporters of the Muslim Brotherhood.

The supporters have been charged with murdering a policeman, as well as the attempted murder of two others during the protests in Cairo last August.

They were also found guilty of setting fire to public property including a police station, as well as seizing police weapons during violent clashes between Brotherhood supporters and the security forces in Rabaa Square in 2013, according to Egyptian state media.

The UK’s foreign secretary William Hague has said he is “deeply concerned” by the news of the death sentences.

“We urge the Egyptian authorities to ensure full respect for defendants’ rights, and hope they will review this unacceptable sentence,” he said in an official statement issued on 24 March.

The US government has also expressed concern about the results of the trial. Marie Harf, deputy US state department spokesperson said a daily press briefing: “We are deeply concerned – and I would say actually pretty shocked by the sentencing to death of 529 Egyptians…”

“Obviously the defendants can appeal, but it simply does not seem possible that a fair review of evidence and testimony, consistent with international standards, could be accomplished with over 529 defendants in a two-day trial. It sort of defies logic.”

She added that the US will continue to talk with the Egyptian government as it transits from an interim to a democratically-elected government, saying “We don’t want to completely cut off the relationship”.

Human rights organisation Amnesty International has condemned the death sentences as a “grotesque example of the shortcomings and selective nature of Egypt’s justice system”.

New York-headquartered group Human Rights Watch has said the sentences are “shocking” and the trials failed to give the defendants “any meaningful opportunity to defend themselves”.

The charges relate to the Brotherhood-backed sit-ins in Cairo’s squares held in mid-2013 in protest at the ousting of former president Mohamed Mursi in July.

The sit-ins lasted for weeks until security forces cleared the squares, resulting in clashes and the death of more than 1,000 people.

Out of the 529 convicted defendants, a total of 382 were not present during the trials. They have been tried and convicted in absentia.

The sentencing is thought to be the biggest capital punishment verdict to date in the history of the Egyptian courts. The court delivered the verdict without hearing the defence arguments, according to local news agency Ahram Online.

The cases are now due to be referred to the Grand Mufti, who is the highest official governing sharia-compliant laws in a Muslim country. The defendants are expected to appeal.