Protesters hold placards as they demonstrate against the execution of prominent Shi'ite cleric Sheikh Nimr al-Nimr outside the Saudi Arabian Embassy in London, Britain January 2, 2016. REUTERS/Neil Hall

WASHINGTON (Reuters) - The U.S. government expressed concern on Saturday that Saudi Arabia’s execution of a prominent Shi’ite cleric, could exacerbate sectarian tensions, and urged all leaders in the Middle East to “redouble efforts” to de-escalate regional tensions.

“We reaffirm our calls on the Government of Saudi Arabia to respect and protect human rights, and to ensure fair and transparent judicial proceedings in all cases,” John Kirby, a spokesman for the U.S. State Department, said in a statement, after the execution of Nimr al-Nimr and 46 other people.

The executions, which also included dozens of al Qaeda members, signaled that the Riyadh government would not tolerate attacks, whether by Sunni jihadists or minority Shi’ites. They stirred sectarian anger, including a march by hundreds of Shi’ite Muslims in Saudi Arabia’s eastern province.

In Hawaii, where President Barack Obama is on vacation with his family, White House deputy national security adviser Ben Rhodes said the administration has urged the Saudis to show restraint regarding respect for human rights.

“We broadly I think have concerns about human rights issues in Saudi Arabia, and again we also would like to see steps taken by Saudi Arabia and other countries to reduce sectarian tensions in the region,” Rhodes said.

Kirby noted that Washington has previously expressed its concern about the Saudi legal system, and raised those concerns at high levels with the Saudi government.

He said the United States also urges the Saudi government to permit peaceful expression of dissent and work together with all community leaders to defuse tensions.‎

“We are particularly concerned that the execution of prominent Shia cleric and political activist Nimr al-Nimr risks exacerbating sectarian tensions at a time when they urgently need to be reduced,” Kirby said.

“In this context, we reiterate the need for leaders throughout the region to redouble efforts aimed at de-escalating regional tensions,” he added.