US Senators call on Trump to order probe into missing Saudi journalist

More than 20 top US Senators have asked President Donald Trump to order an investigation into Saudi journalist Jamal Khashoggi's whereabouts and impose sanctions against anyone found responsible for his mysterious disappearance.

In a letter to Trump, the 22 lawmakers triggered the 2016 Global Magnitsky Act, which gives the President 120 days to decide whether to impose sanctions on any foreign person he determines sponsored or was involved in the disappearance of 59-year-old Khashoggi, an outspoken critic of the Saudi government and Crown Prince Mohammed bin Salman.

Khashoggi, a US resident, vanished on October 2 after entering the Saudi consulate in Istanbul. Turkish authorities suspect he was abducted and murdered by the Saudis.

But Riyadh insists that the journalist had left the building and that murder claims are "baseless".

Trump on Wednesday said he had taken up the case of the journalist and demanded all answers into his disappearance of from the Saudi authorities.

In the letter to Trump, the Senators said the disappearance of the 'Washington Post' columnist suggested that he could be a victim of a gross violation of internationally recognised human rights.

The violations includes "torture or cruel, inhuman, or degrading treatment or punishment, prolonged detention without charges and trial, causing the disappearance of persons by the abduction and clandestine detention of those persons, and other flagrant denial of the right to life, liberty, or the security of person".

"Therefore, we request that you make a determination on the imposition of sanctions pursuant to the Global Magnitsky Human Rights Accountability Act with respect to any foreign person responsible for such a violation related to Mr Khashoggi," the lawmakers said.

"Our expectation is that in making your determination you will consider any relevant information, including with respect to the highest-ranking officials in the Government of Saudi Arabia," the lawmakers said.

The letter was penned by the top Republican and Democrat on the Senate Foreign Relations Committee, chairman Senator Bob Corker and ranking member Senator Bob Menendez, along with the leaders of the appropriations subcommittee for the State Department, Senator Lindsey Graham and Democrat Senator Patrick Leahy.

Earlier in the day, Trump expressed deep disappointment over the situation.

"We are very disappointed to see what is going on. Don't like it. Don't like it at all. And are going to get to the bottom of it," Trump told reporters in response to a question.

"This is a bad situation. We cannot let this happen. To reporters and to anybody, we cannot let this happen. We are going to to the bottom (of it)," he said.

Trump said he and the First Lady Melania had received a letter from Khashoggi's fiancee Hatice Cengiz.

"We are in contact with her now. And we want to bring her to the White House. It's very sad situation. It's a very bad situation," he said.

White House National Security Advisor John Bolton and White House Senior Advisor Jared Kushner spoke to Saudi Arabian Crown Prince Mohammed Salman on Tuesday about the missing journalist.

Secretary of State Mike Pompeo then had a follow up call with the Crown Prince to reiterate the US' request for information.

"In both calls they asked for more details and for the Saudi government to be transparent in the investigation process. We will continue to monitor this situation and provide updates as available," White House Press Secretary Sarah Sanders said.