Saudi Arabia’s King Salman bin Abdulaziz said he was heartbroken over a suicide bombing that killed 21 people and that anyone linked to the attack or who sympathizes with it will be brought to justice, state news agency reported Sunday.

“We were pained by the enormity of the crime of this terrorist aggression which contradicts Islamic and humanitarian values,” the king said in a message to Crown Prince Mohammed bin Nayef, who is also the interior minister.

“Any participant, planner, supporter or sympathizer with this heinous crime will be held accountable, tried and will receive the punishment he deserves,” he said, adding that Saudi Arabia would never stop fighting militants.

On Friday, a suicide bomber blew himself up during prayers at a mosque in the eastern village of al-Qadeeh, killing at least 21 and wounding 81 others.

Salih bin Abdulrahman Salih Al Ghishaami

On Saturday, the country’s authorities identified Saudi national Salih bin Abdulrahman Salih Al Ghishaami as the suicide bomber, Al Arabiya News Channel reported.

Authorities arrested 26 members of a cell affiliated with the Islamic State of Iraq and Syria (ISIS), who claimed responsibility for Friday’s attack, Saudi Ministry of Interior spokesman Maj. Gen. Mansour al-Turki told Al Arabiya.

“His name was Salih bin Abdulrahman Salih Al Ghishaami, a Saudi national. He was wanted by security services for belonging to a terrorist cell receiving directions from Daesh [ISIS] abroad,” the interior ministry said in a statement carried by the official Saudi Press Agency.

Al-Qishaami’s father had been “detained for a while,” Turki added.

“The cell was discovered last month, and so far 26 of its members, all Saudi nationals, have been arrested,” the interior ministry said.

Separately, it was revealed that five members of the same cell were responsible for the death of a Saudi soldier two weeks ago, a statement from the ministry said.