Washington (CNN) A leading Republican senator said Thursday that he believes Saudi journalist Jamal Khashoggi was murdered and that "there is no question the Saudis did this."

Senate Foreign Relations Chairman Bob Corker told CNN that the "intel points directly" to Saudi Arabia for the disappearance of Washington Post columnist Jamal Khashoggi and said the Saudis need to "produce" the 59-year-old father of four to dispel concerns.

"Everything points to Saudi Arabia, and it would appear he's not alive," Corker said. "I would think that if it were Saudi Arabia and he was alive, with all that's happening right now, they would produce him."

South Carolina Sen. Lindsey Graham, a hawkish Republican who has counted himself a strong supporter of Saudi Arabia, said on CNN's "Erin Burnett OutFront" Thursday evening that it looked "increasingly likely" Khashoggi was dead and "all the indicators" pointed to Saudi Arabia.

"They need to account, Saudi Arabia does, for what happened in the consulate," Graham said.

The comments from the top Republican voices highlight a growing tension between Congress, which is calling for action on Khashoggi, and the White House, where President Donald Trump has indicated he's aware of Saudi responsibility but signaled that he's unwilling to take punitive steps, particularly ending arms sales to the kingdom because of the US jobs they generate.

On Thursday, Trump said "what happened is a terrible thing, assuming that happened. I mean, maybe we'll be pleasantly surprised, but somehow I doubt it. We'll be taking it very seriously." He added that "we're looking at it. We'll be having a report out soon."

The prominent Saudi journalist and critic of the regime has been missing for more than a week after going to the Saudi consulate general in Istanbul to obtain wedding papers.

Turkish officials believe Khashoggi was killed inside the consulate, which Saudis deny but have not been able to provide proof he left the consulate safely.

US intelligence intercepts indicating Saudi Arabian officials discussed a plan to lure Kashoggi back to the kingdom will likely further drive the standoff between lawmakers and the President.

'A sense of arrogance'

Lawmakers Wednesday triggered an investigation that could pave the way for sanctions against Saudi Arabia. Senators have tried to limit arms sales to Saudi Arabia in the past because of the civilian deaths in Yemen. The idea is gaining renewed traction. Congress has the final say on arms deals, as they go to lawmakers for a 15-day review, and lawmakers can block sales.

Sen. Bob Menendez, a New Jersey Democrat, put a hold on a the sale of tens of thousands of precision-guided munitions kits to Saudi Arabia and the United Arab Emirates in June- over concerns they were perpetuating the conflict in Yemen. That block is still in place.

Corker said there has been a declining relationship between Saudi Arabia and Congress, and described a "sense of arrogance" in the way the kingdom deals with lawmakers. The Tennessee Republican, who has been a vocal critic of Trump's, would not say if he has confidence in the President's handling of the affair yet.

Graham said in his CNN interview Thursday evening that he had "no reason to believe" Trump would not act decisively.

Trump said Thursday that he is reluctant to take action, particularly on the issue of arms sales. "There are other things we can do," he told reporters at the White House.

"I don't like the concept of stopping an investment of $110 billion into the United States because you know what they're going to do, they're going to take that money and spend it in Russia or China," Trump said, referring to US arms deals with Saudi Arabia. "If it turns out to be as bad as it might, there are certainly other ways to handle the situation."

"Let's find out what the problem is first," Trump said.

The US signed a nearly $110 billion defense deal with Saudi Arabia in May 2017, when Trump made Saudi Arabia a stop on his first foreign trip as President. The stop was seen, in part, as an endorsement of the strong relationship between Trump, his son in law and senior adviser and the de facto Saudi ruler Crown Prince Mohammed bin Salman, who is known as MBS.

Bruce Riedel, director of the Brookings Intelligence Project, notes that cutting off arms sales to Saudi Arabia would be "the best way to hurt MBS where it really matters to him -- it would mean he would have to stop the war in Yemen." Riedel notes that lawmakers have "tried in the Senate and they've always fallen four or five [votes] short."

It's possible to cut off sales, Riedel said, "but it would mean getting Republicans on board." Corker, speaking to reporters Wednesday, indicated it was a strong possibility. Asked if he thought arms sales to Saudi Arabia were at risk, Corker replied, "oh definitely."

Trump acknowledged Wednesday in a phone interview with Fox News that "it's looking a little bit like" the Saudi government is behind the disappearance of Khashoggi, a former Saudi royal insider who became a critic of the Saudi regime.

He added that blocking arms sales to Saudi Arabia "would be hurting us."

Asked about the reports Thursday in another Fox News phone interview, Trump said US has investigators "over there" and is working with Turkey on the matter.

"We'll probably know in the very short future," Trump said on "Fox and Friends." "We have incredible people and incredible talent working on it. We don't like it. I don't like it. No good."

A Turkish diplomatic official denied that the US has sent investigators to Turkey to look into Khashoggi case, saying the reports are "not true."

Asked about the President's comments that the US has investigators on the ground, the FBI would not confirm and would not comment.

CNN has reported that there is no indication as yet that the FBI is involved in Khashoggi investigation, but Vice President Mike Pence has said the US stands ready to assist.

'Frank' phone calls

Prince bin Salman reached out to the White House earlier this week to speak with Kushner after it became clear he and the royal court were getting blamed for Khashoggi's disappearance, according to a person familiar with the call.

While bin Salman reached out specifically to Kushner, his established White House interlocutor, to deny the accusations, national security adviser John Bolton also joined the call, and later, Secretary of State Mike Pompeo had his own conversation with the crown prince.

The person described the calls as frank.