At least three people were killed on Monday after a suicide bomber blew himself up at a mosque in the Saudi city of Najran, close to the Yemeni border, Al Arabiya News Channel reported.

The worshippers had gathered for the evening Maghreb prayers when the attack took place. According to AFP, 12 people were injured in the blast.

A video posted on Twitter shows worshippers - young and old, scurrying to safety, moments after the suicide attack.

Saudi social media reports claimed that an elderly worshipper, killed in the blast, stopped the suicide bomber near the entrance of the mosque and in the process saved many lives.

Moments after the blast [Video]

 An elderly worshipper saved many lives when he stopped the suicide bomber from going inside the mosque [Photo]