AKIPRESS.COM - A suicide bomber has killed four security officers and injured five others near one of Islam's holiest sites in the Saudi city of Medina, according to the interior ministry, BBC reports.

The bomber detonated his explosives after being stopped outside the Prophet's Mosque, a statement said.

The mosque is the burial place of the Prophet Muhammad and Medina the second-holiest city in Islam after Mecca.

Suicide blasts also struck two other Saudi cities on Monday.

That an attack happened in Medina at such a place is likely to leave Muslims around the world aghast, BBC World Service's Middle East editor, Alan Johnston, says.

Suspicion is likely to fall on so-called Islamic State (IS), he adds.