The White House denied Friday it was seeking to smooth over frayed bilateral ties with Riyadh when a recent US government court filing granted immunity to Saudi Crown Prince Mohammed bin Salman over journalist Jamal Khashoggi's 2018 murder.

"This legal determination has absolutely nothing to do with the merits of the case itself," said White House national security spokesman John Kirby, referring to the civil lawsuit against the crown prince and other Saudis by Khashoggi's fiancee Hatice Cengiz.

Moreover, the determination "has absolutely nothing to do with the bilateral relationship with Saudi Arabia, which as you know, is tense right now," he said, pointing to Riyadh's recent support for the OPEC cartel's decreased oil output, which angered Washington.

President Joe Biden "has been very, very clear, very vocally so, about the brutal and barbaric murder of Mr. Khashoggi," Kirby said.

The White House reaction comes as Amnesty International blasted the Biden administration over granting immunity to the prince, calling the act "a deep betrayal."

The rights group also criticized Riyadh for naming Prince Mohammed prime minister in a royal decree, in a move that sparked suggestions he was looking to skirt exposure in the civil action filed by Khashoggi's fiancee.

"The US government should hang its head in shame. This is nothing more than a sickening, total, deep betrayal, Amnesty's Secretary General Agnes Callamard said in a statement.

"First the evidence of the Crown Prince's involvement in Jamal Khashoggi's murder was disregarded by President Trump, then President Biden's fist bump -- it all suggests shady deals made throughout."

Callamard added that it was "beyond cynical" for the Saudi government to seek to extend immunity to Prince Salman by declaring him prime minister.

"It is disappointing that the US government has given effect to this legal ruse," she said, adding it "sends a deplorable message that those in power...are free to operate above the law with total impunity."

The publisher of the Washington Post, the US paper Khashoggi had contributed to, also slammed the decision.

Fred Ryan, the paper's publisher and CEO, said in a statement that Biden was "granting a license to kill to one of the world's most egregious human-rights abusers who is responsible for the cold-blooded murder of Jamal Khashoggi, a Washington Post Columnist."

But White House spokesman Kirby said Biden "has worked to hold the regime accountable."

Kirby also pointed to Biden's order for a review of the US-Saudi relationship, which has been extremely close for decades.

Biden wants to make sure the relationship "is serving the interests of our national security and the American people," he said.

The killing four years ago of Khashoggi, a Saudi insider-turned-critic, in the kingdom's Istanbul consulate temporarily turned Prince Mohammed into a pariah in the West.

His lawyers previously argued he qualifies for the kind of immunity US courts afford foreign heads of state and other high-ranking officials.

The US government had until Thursday to offer an opinion on that matter, if it chose to offer one at all. Its recommendation is not binding on the court.