Transcript for Trump vows to punish Saudi Arabia if they killed missing journalist

down here. Tom? Rob, thank you. Next to the growing tensions over the disappearance of "Washington post" columnist Jamal khashoggi. He's believed to have been murdered, and president trump is vowing to punish Saudi Arabia if it's proved they're behind the alleged murder. And Saudi Arabia says they will retaliate that with force. Ian Pannell reports from istanbul. Reporter: Tonight, president trump threatening action if it's proved the Saudi kingdom is involved in the disappearance of "Washington post" reporter Jamal khashoggi. Telling "60 minutes" -- There's something really terrible and disgusting about that, if that were the case. So, we're gonna have to see. We're going to get to the bottom of it, and there will be severe punishment. Reporter: The Saudi government repeatedly denying any involvement, but now escalating the war of words in a statement, saying, "If it receives any action, it will respond with greater action." Issuing this veiled threat -- "The kingdom's economy has an influential and vital role in the global economy." A clear reference to Saudi oil and its power to control prices. Khashoggi is feared dead. Last seen walking into the Saudi consulate October 2nd. This mystery deepening when Turkish officials alleged a squad of Saudis landed in Turkey the day the reporter vanished, checking into this hotel. The 15 Saudis then mysteriously left the hotel, having only just checked in, got into a van, and headed a few hundred yards down the road to the Saudi consulate. The team then parked up at the back of the consulate, allegedly lying in wait for Jamal khashoggi, who went through the front door a few hours later and never emerged. The national intelligence analyst for the pro-turkish "Daily sabah" newspaper says his sources are convinced khashoggi was murdered. And they have a tape that proves it. And there's no doubt in their minds? There is no doubt, actually. Reporter: He was killed? Yes, yes, he was killed, they say. And the main question is where the body is, you know. Reporter: Can I ask you what happened to Jamal khashoggi, sir? Outside the consulate today, everyone remained tight-lipped. But despite the threat of punishment, president trump not wanting to endanger a multi-billion dollar arms deal with the kingdom. It is 450,000 jobs. It is the best equipment in the world. But if they don't buy it from us, they are going to buy it from Russia, or they are going to buy it from China. Ian, we heard the strong statement from the Saudis in your piece. Tonight, their ambassador in Washington issuing a clarification? Reporter: That's right. A conciliatory statement from the ambassador thanking the administration for not jumping to conclusions. Significant, because the ambassador to Washington is also one of the king's sons. And we're hearing in the last couple of hours that the king himself picked up the phone, spoke to the Turkish president, and thanked him for his help. Taken together, this is a dramatic attempt to lower the rhetoric and ease the tension. But still, no answers from the Saudis about what happened on October 2nd. Tom? Ian, thank you. From Washington tonight, president trump is weighing a new round of family separations

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