Hillary Clinton at the Saban Forum
Hillary Clinton at the Saban Forum Ralph Alswang

Former Secretary of State Hillary Clinton on Sunday criticized Saudi Arabia's execution of 47 people, including prominent Shiite cleric Nimr al-Nimr, saying the move raises "serious questions" that the U.S. needs to ask the country's government.

"Clearly this raises serious questions that we have to raise directly with the Saudi government," the leading Democratic presidential candidate said at a town hall and quoted by CNN.

"We have governments we work with on a number of issues whose policies and values are antithetical to ours, to be just blunt about it. And yet who also have certain interests with us that we are involved in," added Clinton.

Clinton said she joined other leaders in "statements of concern" about the executions, specifically calling out the Obama administration, European governments and human rights groups.

"I think that even our friends who we work with on so many areas should not be immune from our criticism and our questions about rule of law about their treatment of minorities," she stressed.

Al-Nimr’s execution condemnations from Iranian officials and protests across the Shiite Muslim world. In Tehran on Saturday night, demonstrators stormed the Saudi Embassy and threw firebombs at it, setting parts of it ablaze.

On Sunday, Saudi Arabia retaliated and declared it was cutting diplomatic ties with Iran, ordering all members of Iran’s diplomatic mission leave Saudi Arabia within 48 hours.

Iran's Supreme Leader Ayatollah Ali Khamenei has been outspoken about al-Nimr's execution, tweeting Sunday that "Divine revenge will seize Saudi politicians" for the "unfairly spilled blood of oppressed martyr #SheikhNimr."

The execution prompted the State Department to call on Saudi Arabia to respect human rights and permit peaceful dissent.

"We are particularly concerned that the execution of (al-Nimr) risks exacerbating sectarian tensions at a time when they urgently need to be reduced," spokesman John Kirby said.