Members of Congress from both parties are demanding answers of Saudi Arabia's government regarding the disappearance of journalist and Saudi critic Jamal Khashoggi.

Turkish authorities have determined Khashoggi was killed inside the Saudi consulate in Istanbul, according to the Washington Post and others, by a team sent by Saudi Arabia.

Khashoggi is a prominent Saudi dissident who wrote for the Post’s Global Opinions section. He has been living in self-imposed exile in Washington.

“Jamal Khashoggi, a Saudi journalist and dissident, was called to the Saudi embassy in Istanbul on Tuesday, and has not been seen or heard from since,” Rep. Adam Schiff, the top Democrat of the House Intelligence Committee, said in a tweet on Sunday. “Tragically, he is now feared dead. We must demand immediate answers from the Saudi government.”

Saudi Arabia has denied the accusations and said Khashoggi left the consulate soon after he arrived there to obtain a document he needed to get married.

Sen. Bob Corker, R-Tenn., chairman of the Senate Foreign Relations Committee, has personally discussed the issue with the Saudi ambassador to the U.S. and asked the consulate in Istanbul to disclose video footage, according to a statement from his office.

Sens. Chris Coons, D-Del., and Chris Murphy, D-Conn., also of the Foreign Relations Committee, sent tweets directed at the Saudi government demanding to know what happened to Khashoggi.

“Saudi Arabia needs to provide an answer - now - about what happened to Washington Post columnist #JamalKhashoggi. No one has seen him since he entered the Saudi embassy in Istanbul on Tuesday,” Murphy tweeted Friday.

Turkey President Recep Tayyip Erdogan on Sunday called Khashoggi’s disappearance “very, very upsetting,” but stopped short of confirming reports that Saudi Arabia had sent a hit team to kill him.

Foreign policy observers said if the Saudis' involvement is true, it would represent an escalation of a broad crackdown undertaken by Saudi Crown Prince Mohammed bin Salman to stifle criticism.

Khashoggi has written commentary skeptical of Crown Prince Mohammed’s much-hyped reform agenda to modernize the kingdom.

The Trump administration has established a close relationship with the crown prince, who is Saudi Arabia’s de facto ruler, viewing him as key to combating terrorism in the Middle East, and Iran.

But some critics say the Trump administration has grown too close to Crown Prince Mohammed, emboldening his controversial foreign policy pursuits, including his intervention to topple the Houthi rebel group in Yemen.

“Have the Saudis killed their leading dissident and critic of their war in Yemen?” Sen. Rand Paul, R- Ken., said in a Twitter post Sunday.

Human rights groups have accused a Saudi-led coalition, which receives logistical support from the U.S., of causing disproportionate civilian deaths in Yemen. The Trump administration has stood by the Saudis, and recently certified to Congress that the coalition is taking steps to minimize civilian deaths in Yemen.

“If Saudis were involved in Jamal’s death or disappearance, that’s obviously on them,” Aaron David Miller, a former Middle East negotiator in Republican and Democratic administrations, wrote on Twitter. “But in failing to call [Crown Prince Mohammed] out on just about anything, particularly repression at home, Trump Administration has emboldened him and given him sense he can do anything.”