WASHINGTON -- US President Donald Trump on Tuesday affirmed Washington's commitment to its partnership with Riyadh citing national interests, remaining an ambiguous attitude toward the murder of Saudi journalist Jamal Khashoggi.

"The United States intends to remain a steadfast partner of Saudi Arabia to ensure the interests of our country, Israel and all other partners in the region," Trump said in a statement released by the White House.

Calling Saudi Arabia a "great ally" in US fight against Iran, Trump emphasized Riyadh's estimated $450 billion investment in the United States following his trip last year, including expected 110 billion dollars' spending on arms purchase from major US companies.

Meanwhile, the White House host avoided making judgment on the alleged Saudi royal family's involvement in the recent killing of Khashoggi, a columnist for The Washington Post, which has stirred up the international community and invites criticism to the Middle East kingdom.

"Our intelligence agencies continue to assess all information, but it could very well be that the Crown Prince had knowledge of this tragic event -- maybe he did and maybe he didn't!" Trump noted.

US media, citing insiders, reported last week that the CIA had concluded the Saudi Crown Prince Mohammed bin Salman had ordered to kill Khashoggi, while the crown prince himself kept denying the accusations.

"We now know many details of this horrible crime," said Trump in the statement, adding that "we may never know all of the facts surrounding the murder of Mr Jamal Khashoggi."

Trump also revealed that he acknowledged the intention of many US Congress members, who were seeking tough punishment on Saudi Arabia over the Khashoggi incident, but indicated little willingness to echo their call.

"I will consider whatever ideas are presented to me, but only if they are consistent with the absolute security and safety of America," Trump noted.

Khashoggi has been missing since he entered the Saudi consulate in Istanbul on Oct 2. The Saudi authorities had said Khashoggi died in a "brawl" in its consulate.

After releasing the results of its initial investigation, the Saudi Public Prosecution announced that 18 people were arrested for their alleged connections with the killing.

US Treasury imposed sanctions on 17 individuals over their alleged roles in the killing of Khashoggi last week, following US State Department's decision in late October to revoke 21 Saudi suspects' visas.

US Congress has urged a thorough investigation of the case, and threatened to take more actions against Saudi Arabia if those responsible were not held accountable, such as suspending US military sales.