BEIRUT, Lebanon — Bombings rocked three cities across Saudi Arabia on Monday, including near the Prophet’s Mosque in the holy city of Medina, raising the specter of increasingly coordinated attacks by militants seeking to destabilize the monarchy.

A suicide bomber struck near the United States Consulate in the coastal city of Jidda in the morning, wounding two security officers. Then, near dusk, when Muslims were ending their daily Ramadan fasts, other blasts struck near a Shiite mosque in the country’s east and at a security post in Medina, killing four guards, according to the Saudi-owned Al Arabiya television network.

The blasts in Saudi Arabia followed a bloody week in which terrorist attacks caused mass casualties in the largest cities of three predominantly Muslim countries: Turkey, Bangladesh and Iraq.