Saudi Arabia has executed seven men for armed robbery, despite an appeal for clemency by United Nations human rights experts.

The men were sentenced to death in 2009 for crimes committed in 2005 and 2006, when some were younger than 18.

The conservative Islamic kingdom, which applies a strict interpretation of sharia law, has faced criticism by Western countries for its frequent use of capital punishment and trials that human rights groups say do not meet international standards.

The men, from Asir Province in the south of Saudi Arabia, had been due to die last week but were granted a stay of execution while authorities reviewed their case.

They were convicted of theft, including armed robbery, the Interior Ministry said.

Amnesty International and the mens' families said the robberies included one at a jewellery store.

Relatives claimed the seven had been forced to confess to unsolved crimes in the district, in addition to the armed robbery they had carried out. Amnesty said the men later retracted the confessions, which they said had been obtained through torture, without giving details. Saudi Arabia, the world's biggest oil exporter, denies it uses torture.

Human rights activists said the seven men were executed by firing squad yesterday – not beheaded as is customary.

A statement from the UN experts said: "The charges against all seven persons were allegedly fabricated and all seven were convicted following unfair trials."

The Saudi Interior Ministry named the seven men as Sarhan al Mushaikh, Saeed al Amri, Ali al Shehri, Nasser al Qahtani, Saeed al Shahrani, Abdulaziz al Amri and Ali al Qahtani and said they were part of a gang responsible for crimes including armed robbery and theft.

A ministry spokesman said: "By the grace of God, the security authorities were able to apprehend the perpetrators."

He described the sentence to death as "a punishment to deter others".

A group of relatives and friends of the men went to the royal court last week to seek a retrial or pardon from the king, arguing they had been denied proper access to legal representation and their crimes did not warrant execution.

The men were granted a stay of execution but were shot in Abha, the capital of Asir, one of the least developed parts of the country.

A prominent Saudi lawyer and supporter of efforts spearheaded by King Abdullah to reform the judiciary by standardising sentencing and retraining sharia judges, defended the executions.

"We are in a society where we used to leave our shops open and go to pray ... because we were sure nobody would come and steal our stuff. So to have an organised criminal group come and do such a thing, we don't like it," he said.

The lawyer said death sentences were reviewed by an appeal court, the high court and the king's office before the sentence was implemented.

"They don't just do the paperwork. No, they review the judgment," he said.

In January, King Abdullah said he had full confidence in Saudia Arabia's justice system after the UN voiced concern over the trial of a Sri Lankan woman who had been executed.