The New York Times reports: The Islamic State extremist group claimed responsibility Friday for a suicide bombing during midday prayer at a Shiite mosque in eastern Saudi Arabia. The Saudi Health Ministry said at least 21 people had been killed and more than 120 others injured.

It appeared to be the first official claim of an attack inside the kingdom by the Islamic State, which has seized control of much of Syria and Iraq.

The group attributed the attack to a new unit, the Najd Province, named for the central region of Saudi Arabia around Riyadh. But it was unclear whether the attack was planned by Islamic State leaders, initiated independently by a Saudi sympathizer, or merely claimed opportunistically after the fact.

The attack was a sign that Saudi Arabia’s intervention in the sectarian conflict in Yemen may be escalating tensions at home. Members of the Shiite minority in Saudi Arabia, who make up about 15 percent of the population and live mainly in the Eastern Province, have long complained of insults and discrimination by Saudi Arabia’s Sunni majority and its clerical establishment. [Continue reading…]