Saudi security forces arrested a Syrian accused of plotting attacks and his Filipina accomplice in a raid on an illegal explosives factory in Riyadh, the Interior Ministry said over the weekend, according to state news agency SPA. The ministry said those arrested in Wednesday's raid belonged to a "deviant group" – a reference used by Saudi authorities to Al-Qaeda or ISIS. It named the Syrian man as Yaser Mohammad al-Barrazi. Saudi Arabia has this year been grappling with a rising radical Sunni militancy linked to ISIS. The group says it wants to bring about the overthrow of the Gulf Arab states' ruling dynasties and has called on Saudi Sunnis to carry out attacks inside the kingdom. Saudi Arabia has arrested hundreds of alleged sympathizers and last week's raids were the second major security operation in the capital in the past month. Security forces captured two suspected militants and seized weapons and an explosive vest in raids on Sept. 15. This year, ISIS suicide bombers attacked Shiite mosques in the Eastern province and in Kuwait. In August, at least 15 people were killed in an attack on a mosque used by members of a local security force in southwest Saudi Arabia. Two explosive belts and bomb-making equipment were found in the raid Wednesday in the Al-Fayhaa district of Riyadh, SPA reported. Another location, which the ministry said was believed to be a staging post for suicide bombers in the Al-Jazirah district, was also raided, but nothing was found there. The American Embassy in Riyadh Thursday put out a new security warning to U.S. citizens in Saudi Arabia. "The U.S. Embassy has been made aware of information indicating that there are threats against unspecified compounds in which United States citizens reside in the Eastern Province," it said in a statement posted on its website. The embassy gave no specific details on nature of threat. Numerous U.S. energy companies operate in the Eastern Province, where most kingdom's oil wealth is located. Most of their foreign staff live in gated communities with high security.