"We strongly condemn these detestable sectarian practices and affirm that the crime of executing Sheikh al-Nimr will topple the Saudi regime as the crime of executing the martyr (Mohammed Baqir) al-Sadr did to Saddam (Hussein)," al-Maliki said in a statement, referring to the  martyrdom in Iraq of another prominent Shiite cleric in 1980, ITV reported on Saturday.

Saudi Arabia’s execution of  Sheikh Nimr drew angry reactions from Muslims worldwide, with the regime being warned of "repercussions".

Senior Iranian cleric Ayatollah Ahmad Khatami said on Saturday the "Islamic world would cry out" in response to the execution and said he had no doubt that "the pure blood" will bring  the Saudi regime to an end.

Riyadh executed on Saturday 47 people on charges of 'terrorism', according to a statement from the Interior Ministry.

Saudi police has reportedly increased security in the Qatif district of the country's Eastern Province, as protesters gathered in the Shiite majority area.