Several countries are threatening to exert pressure on Saudi Arabia over the disappearance of Jamal Khashoggi, a Saudi journalist who was last seen entering the Saudi Arabian consulate in Istanbul, Turkey in early October. Specifically, some lawmakers from the United States and the United Kingdom are considering ending the sale of arms and military equipment to the Gulf nation unless Khashoggi is found.

Many fear that Khashoggi, who worked as a columnist for the Washington Post and was often critical of Saudi leadership, was murdered inside the building.

According to a report from Reuters, Saudi officials have denied the accusations; however, Turkish police are currently investigating the incident. According to a report from CNBC, Turkish police have told US officials that they possess audio and visual evidence proving the murder.

“Just spoke to the King of Saudi Arabia who denies any knowledge of whatever may have happened ‘to our Saudi Arabian citizen,'” said US president Donald Trump in a tweet on Monday. “He said that they are working closely with Turkey to find answers. I am immediately sending our Secretary of State to meet with King!”

According to Reuters, Trump told reporters that if Khashoggi was killed in the Saudi’s consulate, the response would be “severe punishment.”

Other prominent US politicians have called for a thorough investigation and tough consequences if Khashoggi was murdered. Marco Rubio, a Republican senator from Florida, said that it would be necessary for the US to end arms sales to Saudi Arabia or risk “losing credibility” on the world stage.

“If we do not take action, including potentially arms sales, as a result of this, if it turns out to be what they say it is, then we are not going to be able to with a straight face or any credibility confront Putin or Assad or Maduro in Venezuela or frankly confront the Chinese and their human rights violations,” said Rubio while speaking on CBS’s Face the Nation on Sunday according to Reuters.

However, Trump also stated that halting weapons sales to the Gulf Kingdom was not an option currently being explored.