Saudi Arabia's Crown Prince Mohammed bin Salman described slain journalist Jamal Khashoggi as a "dangerous Islamist" after his disappearance weeks ago, according to US media reports.
The reported phone call with President Donald Trump's son-in-law Jared Kushner and National Security Adviser John Bolton allegedly took place before Saudi Arabia publicly acknowledged that Khashoggi had been killed in its consulate in Istanbul.
Citing people familiar with the call, the New York Times and the Washington Post reported that the crown prince said Khashoggi belonged to the Muslim Brotherhood - outlawed by Riyadh and its Arab allies - and urged Kushner and Bolton to preserve the US-Saudi alliance.
Saudi Arabia has denied the media reports. Prince Salman deplored the killing and refutes all allegations against him.
A critic of Mohammed bin Salman's reform programme in Saudi Arabia, Khashoggi was killed after entering the consulate on October 2.
The kingdom has faced international condemnation for the journalist's murder and its shifting official accounts of his disappearance last month.
Saudi authorities initially stated the journalist left the consulate, before backtracking and admitting on October 20 he was killed by "rogue" operatives.
"The attempt to criticise Khashoggi in private," the Post noted, "stands in contrast to the Saudi government's later public statement decrying his death as a 'terrible mistake' and 'terrible tragedy'".
According to the Post, Kushner has been lobbying on behalf of the heir to the Saudi throne and has emphasised the strategic importance of the US-Saudi alliance.
Some officials at the US State Department however said they are considering a range of disciplinary measures, including a demand to end the Saudi-led blockade of Qatar or wind down the war in Yemen, where a Saudi-UAE military coalition is fighting the country's Houthi rebels.