Rep. Joaquin Castro (D-Texas) on Friday accused senior White House adviser Jared Kushner of orchestrating the killing of Saudi-born Washington Post columnist Jamal Khashoggi.

Castro, who serves on the House Intelligence Committee, told CNN he did not have substantial evidence to support his claim, but repeatedly cited media reports on the subject.

Castro cited unspecified reporting "that Jared Kushner may have, with U.S. intelligence, delivered a hit list, an enemies list, to the crown prince, to MBS, in Saudi Arabia and that the prince may have acted on that."

CNN host Poppy Harlow attempted to clarify what reporting Castro was referring to, saying CNN had not reported on that accusation.

Castro continued, saying "I've seen reporting to that effect ... That needs to be investigated."

Castro later clarified his comments, tweeting that he did not intend to accuse Kushner of orchestrating the killing and noting he meant to express that he wants Congress to open an investigation into whether U.S. intelligence was shared with Saudi Arabia that may have led to Khashoggi's death.

He also linked media reporting that highlighted ties between the Trump administration and Saudi Arabia.

"To be clear, I did not intend to accuse @jaredkushner of orchestrating anything," Castro tweeted. "Based on press reporting, I'm asking for Congress to open an investigation of whether any US Intelligence was shared with Saudi Arabia that led to political persecution or killing of #Khashoggi."

White House press secretary Sarah Huckabee Sanders later condemned Castro's remarks, calling the allegation "outrageous" and "slanderous."

".@JoaquinCastrotx's allegation is an outrageous slanderous lie without a shred of proof, it's reprehensible for a sitting Congressman and supposed 'news' outlets to continue citing an article that used unnamed sources and was completely debunked," Sanders tweeted Friday afternoon.

Khashoggi has been missing for more than two weeks and was last seen entering the Saudi Consulate in Istanbul.

Kushner, the son-in-law of President Trump, and Saudi Arabia's Crown Prince Mohammed bin Salman have a well-documented relationship, though no one before Castro has accused Kushner of having any involvement in the death of Khashoggi.

On Thursday, Trump took his strongest stance against Saudi Arabia, threatening "very severe" consequences if the country is found to be responsible for the killing.

Until Thursday, Trump and his top aides had been reluctant to criticize the Saudis over Khashoggi's disappearance and the president even floated the possibility that "rogue killers" were responsible for the alleged attack.

--Updated at 3:21 p.m.