The United States has called on Saudi Arabia to have fair judicial proceedings and respect human rights after Riyadh executed prominent Shia cleric Sheikh Nimr al-Nimr and 46 other people.

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 US State Department, said in a statement on Saturday.

The Saudi Interior Ministry announced earlier on Saturday that Sheikh Nimr along with 46 others, who were convicted of being involved in “terrorism” and adopting a “Takfiri” ideology, had been put to death.

Sheikh Nimr, a critic of the Riyadh regime, was arrested in 2012 in the Qatif region of Shia-dominated Eastern Province, where peaceful anti-regime demonstrations were held at the time.

He was charged with instigating unrest and undermining the kingdom’s security, making anti-government speeches and defending political prisoners. He had rejected all the charges as baseless.

Kirby said Washington had previously expressed its concern about the legal system in Saudi Arabia and that it addressed those concerns at high levels with the Saudi government.

He said the United States maintains that the Saudi government should allow peaceful expression of dissent and cooperate 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.

Also, White House deputy national security adviser Ben Rhodes said that the Obama administration had previously called on the Saudis to exercise restraint concerning 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.

Saudi Arabia’s Eastern Province has been the scene of demonstrations since February 2011, with protesters demanding reforms, freedom of expression, release of political prisoners and an end to widespread discrimination against people of the oil-rich region. Several people have been killed and many others injured or arrested during the rallies.

International rights bodies have criticized Saudi Arabia for its grim human rights record, arguing that widespread violations continue unabated in the country.