Pictures are just coming in from Saudi Arabia where the state broadcaster is reporting a suicide bomber has detonated a device at the second-holiest site in Islam.
It reportedly happened near the security headquarters of the Prophet's Mosque in Medina.
Early accounts say the suicide bomber and two security officers were killed in the attack.
The blast follows two others in the Saudi cities of Qatif and Jeddah today, including a suicide bombing near the U.S. consulate in Jeddah.
The attacks come as Muslims start Eid al-Fitra festivities marking the last day of the Muslim holy month of Ramadan.