Washington, Oct 15 US President Donald Trump on Monday said that he spoke to Saudi King Salman over the disappearance of journalist Jamal Khashoggi and will send Secretary of State Mike Pompeo to discuss the situation with the monarch.In a morning tweet, Trump said that the King denied any knowledge of the journalist's whereabouts. Khashoggi, a columnist for The Washington Post and a Saudi royal insider-turned-critic, entered his country's consulate in Istanbul, Turkey, on October 2 and has not been seen since."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 the answer. I am immediately sending our Secretary of State to meet with King," Trump tweeted.Turkish intelligence officials say they have audio and visual evidence that shows Khashoggi, a permanent resident of the US in self-imposed exile, was killed inside the Saudi consulate in Istanbul.Saudi Arabia, however, denies any involvement in his disappearance and maintains that he left the consulate the same afternoon. Trump's comments came as the Saudis gave Turkish authorities permission to search the kingdom's consulate in Turkey, where Turkish officials believe the journalist was killed and dismembered, the New York Times reported.Saudi officials first granted permission for the consulate to be searched last week, but later asked for a delay. As per reports, Turkish officials also want to search the nearby Consul General's residence and have repeatedly accused the Saudis of failing to cooperate with their investigation.Diplomatic pressure is growing on the Saudis to give a fuller explanation. The UK, France and Germany demanded a "credible investigation" into the events and Trump warned of serious retribution if the Saudis were found to be behind Khashoggi's possible death.A joint Turkish-Saudi working group into the case has been proposed, but the results of a separate, internal Saudi investigation should be made public soon, a Saudi official told CNN.The Saudi official said that a royal decree was issued on Friday directing the public prosecutor to conduct an internal investigation, based on intelligence shared by Turkey.On Sunday, Washington and Riyadh traded a series of threats, with Trump warning of the potential for "severe punishment" and Saudi officials threatening to retaliate if the US imposed sanctions. Riyadh later softened its tone."There's something really terrible and disgusting about that, if that were the case. So we're going to have to see," Trump said in a "60 Minutes" interview broadcast on Sunday. "We're going to get to the bottom of it and there will be severe punishment."The news that Turkey could enter the consulate came a day after the Saudi King called Turkish President Recep Tayyip Erdogan to discuss the Khashoggi case.The two leaders agreed on a joint working group to look into the journalist's disappearance.