China on Monday condemned a suicide attack that killed 21 worshippers at a mosque in eastern Saudi Arabia.

"The Chinese side firmly opposes terrorism of all forms and supports the Saudi side's efforts to safeguard national security and stability," Foreign Ministry spokeswoman Hua Chunying said at a daily news briefing.

She also extended condolences to the victims and sympathies to the injured.

On Friday, a suicide attack that targeted "Imam Ali" Mosque in Qudaih area of the Saudi city of Qatif killed at least 21 worshipers and injured more than 100.