Riyadh: Saudi Arabia on Sunday said it has arrested 135 suspects for "terrorism" offences, after the kingdom's participation in air strikes against Islamic State group extremists raised concerns about possible retaliation.
The suspects include 26 foreign nationals, among them "16 Syrians and three Yemenis", interior ministry spokesman General Mansour al-Turki said, cited by the official Saudi Press Agency.
The detainees belong to "suspect groups... That terrorism united", and their arrests followed "repeated attempts to harm the security and stability of the homeland", Turki said without specifying when they were detained.
Forty of the suspects had gone to "zones of conflict, joined extremist groups and trained in the handling of weapons... Before returning to the kingdom to destabilise the country," Turki said.
He added that 54 others were implicated in the "financing, recruitment, propaganda and manufacture of explosives... In aid of extremist groups".
Seventeen suspects were linked to unrest and armed attacks on security forces in Awamiya, a community in Eastern Province just west of Dammam city.
Awamiya has been a focus for clashes between security forces and minority Shiite protesters.
Turki said the detained foreign suspects included an Egyptian, a Lebanese, an Afghan, an Ethiopian, a Bahraini and a stateless person.
The arrests come as Saudi Arabia, the United Arab Emirates, Jordan and Bahrain take part in US-led air strikes against the IS extremist group in Syria.
Saudi pilots who took part in the initial air raids in September received online death threats after photos were published of those involved, among them a son of the crown prince.
The kingdom's Grand Mufti Sheikh Abdul Aziz al-Sheikh has said Al-Qaeda and IS "have nothing to do with Islam and (their proponents) are the enemy number one of Islam".
Last week an IS-linked media group released a video claiming to show the shooting in Riyadh of a Danish national by its "supporters", the US-based monitoring group SITE said.
Denmark has confirmed that one of its citizens was shot and wounded in the Saudi capital on November 22.
The video carries an audio recording, allegedly of IS leader Abu Bakr al-Baghdadi saying that Saudi rulers will see "no more security or rest".