Saudi Arabia and Kuwait have arrested two members of the Egyptian Muslim Brotherhood at Cairo's request for committing violence in Port Said before fleeing abroad, Egypt's prosecutor's office said on Wednesday.
The arrests are the first reported cases of Egypt's Gulf allies detaining members of the Islamist group on its behalf.
Saudi Arabia and Kuwait are among the Gulf nations that have pumped billions of dollars into Egypt since the army ousted Islamist President Mohamed Mursi last July following mass protests against him.
"The office of the public prosecutor has received a notification of the arrest of Akram Al Shaer by the Kingdom of Saudi Arabia, and the accused Mohamed Al Qabouti by the state of Kuwait," the office said in a statement.
The men were accused of inciting the killing of citizens and of assembling mobs to break into a police station and destroying property in the city of Port Said in 2013, the statement said.
Egypt designated the Brotherhood a terrorist organisation in December, escalating a state crackdown on the group. Hundreds of members and supporters have been killed, and thousands more, including the movement's leadership, are in jail.
Riyadh took the same step to declare the group a terrorist organisation on Friday. Kuwait, home to a more open political environment that includes Islamists close to the Brotherhood, has not.
Both countries have backed Egypt's new government and sent billions of dollars to help prop up its struggling economy.
Shaer was head of the health committee in Egypt's parliament during Mursi's presidency. Qabouti is a less well-known member of the group.