The official asked not to be identified discussing the matter because of its sensitivity.

The State Department said on Thursday that Washington had already taken action over Khashoggi's killing.

The crown prince is widely believed to be the kingdom's de-facto ruler and has been linked to the slaying on Khashoggi at the Saudi consulate in Istanbul last October. Some aides said they still hoped to receive it by early next week if not on Friday, but the administration said it did not feel the need to send one.

The White House said in a statement that Congress can't force the president to act.

Secretary of State Mike Pompeo sent a letter to Congress outlining actions taken by the US against individuals believed to be involved in the killing, but stopped short of describing who was ultimately responsible.

The communications were analysed after USA intelligence agencies searched through bin Salman's texts and calls, which - according to The Times - is a routine procedure.

In this photo fromFebruary 4, 2019, Saudi Arabia Foreign Minister Adel al-Jubeir speaks with reporters during an European Union-Leagues Arab States ministerial meeting in Brussels. "I don't know, probably, maybe through security channels but I am not aware that there was". Saudi Arabia's public prosecutor has indicted 11 Saudi nationals for the murder and requested the death penalty for five of them.

"Two days ago in Washington, D.C. we also evaluated this issue with foreign ministers from other countries", Cavusoglu said.

"We continue to call for a thorough and credible investigation in line with everything that we have said on Khashoggi case over the past months", she said. "But don't judge us before this is complete".

Callamard said she was still waiting for a response from Saudi authorities to a request she made three weeks ago for an invitation to visit the kingdom.

The murder was met with worldwide outrage and considerably hurt the image of the crown prince.

Congressional leaders triggered the Magnitsky Act in October, giving the administration 120 days, until February 8, to report back on who was responsible for the death of Khashoggi, a USA resident killed at the Saudi consulate in Istanbul, Turkey, and whether it would impose sanctions on that person or persons.

A year before Saudi journalist Jamal Khashoggi was killed, Crown Prince Mohammed bin Salman told an aide he would use "a bullet" on the journalist if he did not return home and end his criticism of the government, the New York Times reported on Thursday.

The conversation was intercepted by USA intelligence agencies, as part of routine efforts by the National Security Agency and other agencies to capture and store the communications of global leaders, including allied ones, The Times said.