Saudi Arabia executed 47 people on Saturday for terrorism, mostly suspected Al Qaeda members but also a prominent Shi'ite Muslim cleric, Nimr Al Nimr, Interior Ministry said in a statement broadcast on state television.

The kingdom had detained thousands of militant Islamists after a series of Al Qaeda attacks from 2003-06 that killed hundreds, and has convicted hundreds of them.

However, it also detained hundreds of members of its Shi'ite minority after protests from 2011-13, during which several policemen were killed in shooting and petrol bomb attacks. Several of he Shi'ites have been sentenced to death.

Saudi Arabia's main regional rival, Iran, has warned that executing Nimr "would cost Saudi Arabia dearly".

The Shiite nation summoned Saudi Arabia's charge d'affaires in Tehran on Saturday to protest the execution, Iranian state television said.

Earlier in the day, the Saudi Interior Ministry statement began with Koranic verses justifying the use of execution and state television showed footage of the aftermath of al Qaeda attacks in the last decade. Saudi Grand Mufti Sheikh Abdulaziz Al Al Sheikh appeared on television soon after to describe the executions as just.

The executions are Saudi Arabia's first in 2016. At least 157 people were put to death last year, a big increase from the 90 people killed in 2014.-Reuters