0720 GMT June 19, 2019
"Yes, this is of serious concern, the apparent enforced disappearance of Mr Khashoggi from the Saudi consulate in Istanbul," UN human rights spokeswoman Ravina Shamdasani told a Geneva news briefing.
"If reports of his death and the extraordinary circumstances leading up to it are confirmed, this is truly shocking," she said.
"We call for cooperation between Turkey and Saudi Arabia to conduct a prompt and impartial investigation into the circumstances of Mr Khashoggi's disappearance and to make the findings public," Shamdasani said. The two countries have such an obligation under both criminal law and international human rights law, she said.
The disappearance of Khashoggi, previously a prominent newspaper editor in Saudi Arabia and an adviser to its former head of intelligence, has sparked global concern, particularly after Turkish sources said over the weekend that authorities believed he had been killed inside the consulate.
The US and other Saudi allies have also taken a cautious approach toward Khashoggi’s disappearance, expressing concern but refraining from any strong comments against the oil-rich kingdom.
“I am concerned about it. I don’t like hearing about it,” President Donald Trump told reporters as he returned to Washington from Florida. “And hopefully that will sort itself out. Right now, nobody knows anything about it.”
US Secretary of State Mike Pompeo called on Saudi Arabia to investigate the strange disappearance of the journalist, adding “to be transparent about the results of that investigation”.
Turkish President Tayyip Erdogan on Monday asked Riyadh to prove its claim that Khashoggi had left the Saudi consulate in Istanbul, while Washington urged Saudi Arabia to support an investigation into his disappearance.
UN human rights experts also have called for an immediate international investigation into the disappearance, with one insisting the case "should not be politicized."
The experts said the "perpetrators and masterminds" who might be responsible for the disappearance of Khashoggi, a contributor to the Washington Post who has criticized the Saudi government, "should be identified and brought to justice."
The independent experts expressed concern that Khashoggi's criticism of recent Saudi policies might be "directly linked" to his disappearance.
Meanwhile, the EU added its weight to international demands for official clarifications about what happened to missing Saudi journalist.
EU foreign affairs chief Federica Mogherini said the bloc stands side-by-side with the US in urging authorities to clear up the journalist's disappearance.
She told AP: "On this, let me subscribe 100 percent (to) what (US) secretary (of state Mike) Pompeo said just a few hours ago. We are fully aligned with the United States on this, with the US position on this."
Mogherini added: "We expect a thorough investigation and full transparency from the Saudi authorities on what has happened."
‘Friendships depend on shared values’
Britain’s Foreign Minister Jeremy Hunt also called on Saudi Arabia to explain what happened to Khashoggi.
“Just met the Saudi ambassador to seek urgent answers over Jamal Khashoggi,” Hunt said on Twitter on Tuesday.
“Violence against journalists worldwide is going up and is a grave threat to freedom of expression. If media reports prove correct, we will treat the incident seriously - friendships depend on shared values.”
Saudi Arabia has agreed to let Turkish authorities search the kingdom's Istanbul consulate, the Turkish Foreign Ministry said Tuesday.
"Saudi authorities said they were open to cooperation and that a search can be conducted at the consulate building," the ministry spokesman Hami Aksoy said in a statement.
The search will take place as part of the official investigation, which was being conducted "in an intense manner", he said without giving any date.
Reuters, AP and AFP contributed to the story.