Jared Kushner was reportedly the target of Saudi efforts to influence the Trump administration.

Kushner, the president’s son-in-law and senior adviser, developed a close relationship with Saudi Arabia's Crown Prince Mohammed bin Salman, and are even on a first-name basis, according to a New York Times report.

The relationship has cemented the crown prince in Kushner's priorities, as he defended him to the Trump administration after US intelligence agencies concluded he was responsible for the death of journalist Jamal Khashoggi.

Jared Kushner reportedly developed a close relationship and kept in contact with Saudi Arabia's Crown Prince Mohammed bin Salman, after being targeted by Saudi officials in an effort to woo the Trump administration.

Kushner, President Donald Trump's son-in-law and senior adviser, also reportedly kept in regular contact with the crown prince, with whom he was on a first-name basis.

The two men even regularly spoke on the phone — even after US intelligence agencies concluded he was responsible for the death of journalist Jamal Khashoggi, according to a Saturday New York Times report.

Khashoggi, a US-based columnist for The Washington Post, disappeared after entering the Saudi consulate in Istanbul, Turkey, on October 2. Turkish officials leaked gruesome details to US and Turkish pro-government media in the following weeks about Khashoggi's violent death.

Read more: Here's everything we know about the troubling disappearance and death of Saudi journalist Jamal Khashoggi

The Times, citing former officials, text messages, and emails, reported that Kushner and the crown prince have been in close contact for nearly two years, despite efforts from the White House chief of staff, John Kelly, to rein in one-on-one communications with foreign leaders.

President Donald Trump meets with Mohammed bin Salman, Deputy Crown Prince and Minister of Defense of the Kingdom of Saudi Arabia, in the Oval Office at the White House Mark Wilson/Getty Images

Despite the White House's communications protocol, the crown prince and his aides reportedly continued to pursue contact with Kushner beginning around Trump's inauguration to curry favor for the prince's policies and authority in the region.

Three former senior US officials told The Times that Kushner's lack of political experience could leave him vulnerable to being manipulated by the Saudis.

Kushner's close contact with Saudi officials has been previously reported. The Washington Post reported last month that the crown prince had told Kushner in a phone call that Khashoggi was a "dangerous Islamist" just days after the journalist went missing.

Their relationship may have been the catalyst for Kushner's previously efforts to persuade Trump to stand by Crown Prince Mohammed through the uproar over Khashoggi's killing.

Trump's reluctance to back the conclusion by US intelligence that Saudi Arabia orchestrated Khashoggi's killing has prompted outcry from lawmakers. The Senate even voted to advance a measure that would compel the US to withdraw its support for the Saudi-led efforts in Yemen's civil war.

"We have to be able to work with our allies," Kushner said in an October interview with CNN, before crediting Saudi Arabia as "a very strong ally in terms of pushing back against Iran's aggression."