President Donald Trump said Monday that the king of Saudi Arabia had denied any knowledge of the whereabouts of missing journalist Jamal Khashoggi, and that he was sending Secretary of State Mike Pompeo to meet with the Saudi leader.

“Just spoke to the King of Saudi Arabia who denies any knowledge of whatever may have happened ‘to our Saudi Arabian citizen,’” Trump tweeted.

“He said that they are working closely with Turkey to find answer. I am immediately sending our Secretary of State to meet with King!” Trump wrote.

Just spoke to the King of Saudi Arabia who denies any knowledge of whatever may have happened “to our Saudi Arabian citizen.” He said that they are working closely with Turkey to find answer. I am immediately sending our Secretary of State to meet with King! — Donald J. Trump (@realDonaldTrump) October 15, 2018

Soon after, the State Department said that Pompeo would be traveling to Riyadh "at the request of President Trump."

Moments after Trump's tweet, the president told reporters at the White House that, from his conversation with King Salman, "it sounded to me like maybe these could've been rogue killers."

Trump said the King denied any involvement. When asked if he believed the denial, the president replied, "all I can do is report what he said."

Khashoggi, a Saudi citizen and critic of the government, vanished on Oct. 2 after entering the Saudi consulate in Istanbul, triggering a major diplomatic crisis for the kingdom.

Turkish authorities have told U.S. officials that they have recordings from inside the Saudi consulate in Istanbul that provide evidence that the missing journalist was killed inside.

Trump told CBS’s “60 Minutes” in comments that aired Sunday night that Saudi Arabia could face "severe punishment" if it's confirmed the missing journalist was killed.

"We're going to get to the bottom of it and there will be severe punishment," Trump said.

Asked whether Saudi Crown Prince Mohammed bin Salman gave an order to kill Khashoggi, Trump said "nobody knows yet, but we'll probably be able to find out."

The Saudi government has denied and condemned the allegations that it killed Khashoggi.

Saudi Arabia said Sunday it rejected any “threats” of economic or political pressure after Trump's warning. The statement carried by the state-run Saudi Press Agency also cautioned that the kingdom would respond to any steps taken against it with “greater action.”