(CNN) Donald Trump has never been shy about talking up his close business relationships with the Saudis.

"I get along great with all of them," Trump said of the Saudis at a 2015 campaign rally in Mobile, Alabama. "They buy apartments from me. They spend $40 million, $50 million. Am I supposed to dislike them? I like them very much!"

But the President's reluctance to take decisive action after the disappearance this month of dissident journalist Jamal Khashoggi -- a US resident -- from the Saudi consulate in Istanbul has renewed questions about the potential conflicts posed by Trump's long-standing ties to the kingdom's royal family.

"Having a President with global business ties means we've got ongoing worries that policy is going to be affected by his business interests," said Robert Weissman, president of Public Citizen, a nonprofit advocacy group that has tracked potential conflicts of interest involving Trump and members of his administration. "We know that historically the Saudis have spent huge money on Trump properties and we know that since he became a candidate and was elected they have targeted discretionary spending at his hotels."

The president made millions selling apartments in his New York buildings to the kingdom, and the Trump Organization has benefited from Saudi business at its hotels in Washington, New York and Chicago.

Khashoggi, a Washington Post columnist, hasn't been seen since entering the Saudi consulate in Istanbul to retrieve paperwork that would permit him to marry his Turkish fiancee. In recent days Turkish authorities have obtained audio and visual evidence that shows he was murdered inside the consulate, a source familiar with the ongoing investigation told CNN.

Khashoggi's disappearance has triggered a wave of top political and business leaders severing ties with the kingdom pending further details of what happened to him. Media organizations, including CNN, have dropped out of a high-profile investor conference slated for later this month in Riyadh.

Trump said Friday he would call Saudi King Salman "at some point," after senior officials, including son-in-law Jared Kushner, held calls earlier this week with Crown Prince Mohammed bin Salman, with whom Kushner has developed a particularly close personal relationship.

When asked Friday whether it was a mistake for Kushner to have such a close relationship with the crown prince, Trump replied, "Well I don't know if it's any closer than other relationships that people have. We have a lot of very close relationships with a lot of countries. But this is a serious problem."

But the President and his top aides have also indicated reluctance to take concrete action, including bowing to congressional pressure to walk back planned arms sales.

The US signed a major defense deal in Saudi Arabia in May 2017, when Trump made the country his first foreign stop as President -- a visit marked with a lavish sword-dancing celebration.

"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 Thursday. "If it turns out to be as bad as it might be, there are certainly other ways of handling the situation."

So far, however, Saudi Arabia has made only $14.5 billion in such purchases, CNN reported on Friday.

While the President's financial relationships with Russian interests have been the subject of widespread public and legal scrutiny, he's also built ties with Saudis over the years.

In June 2001, he sold the 45th floor of Trump World Tower to the Kingdom of Saudi Arabia for $4.5 million, according to a publicly filed deed for the transaction.

In 2007, the Saudis received permission from the New York City Department of Buildings to combine the residential units into a single space to house the Saudi Mission to the United Nations, public records show. A spokesman for the mission couldn't immediately be reached. The embassy's website lists the mission's address at a different location.

Trump's buildings have also been home to nationals of countries with which the president has had rockier relationships in office, including China.

Trump has reaped other financial benefits from Saudi Arabia and its representatives.

At the Trump International Hotel in Washington, which has served as something of an unofficial headquarters for foreign governments in the Trump era, a lobbying firm for Saudi Arabia paid the hotel more than $270,000 between October 2016 and March 2017.

Trump hotels in New York and Chicago have had a rush of visitors from Saudi Arabia in recent months, according to The Washington Post, and in New York the Trump International Hotel's general manager wrote in a letter to room owners in May that revenue had increased in the first quarter of 2018 due to "a last-minute visit to New York by the Crown Prince of Saudi Arabia."

Mohammed bin Salman himself didn't stay at the hotel, the Post reported, but he typically travels with an enormous entourage and security detail, and members of his party stayed there for five days in March.

Trump also appears to have explored potential deals of his own in Saudi Arabia.

In August 2015, two months after the launch of his presidential campaign, Trump registered eight limited-liability companies that appeared tied to possible deals in the country, according to public records. All of the companies contained "Jeddah," the name of a Saudi Arabian port city, in their title.

That year, Trump's daughter Ivanka Trump told the publication Hotelier Middle East, "Dubai is a top priority city for us. We are looking at multiple opportunities in Abu Dhabi, in Qatar, in Saudi Arabia, so those are the four areas where we are seeing the most interest. We haven't made a final decision in any of the markets but we have many very compelling deals in each of them."

Four of the companies were dissolved or canceled two months after their creation, and the other four were dissolved or canceled in November 2016, after Trump won the election, records show.

A spokeswoman for the Trump Organization said in a statement: "Like many global real estate companies, we have explored opportunities in many markets, that said, we do not have any plans for expansion into Saudi Arabia."

The administration has taken a consistent line on the Khashoggi case, with senior officials echoing the President.

In an interview released Friday, national security adviser John Bolton told conservative radio host Hugh Hewitt: "We need to find out what the facts are, and we need to get this resolved quickly, because if it is another operation, people need to understand that. I think the Saudis themselves are being damaged, because we don't have the facts out."