Saudi Arabia has threatened to use its economic muscle to respond to any punitive measure taken against the kingdom in the wake of the disappearance of a prominent journalist.  In a statement released after President Donald Trump warned that Saudi Arabia would face “ severe punishment” if the government had killed Jamal Khashoggi, the world’s top oil exporter said “if it receives any action, it will respond with greater action”.

“The kingdom affirms its total rejection of any threats and attempts to undermine it, whether by threatening to impose economic sanctions, using political pressures, or repeating false accusations,” the Saudi state news agency quoted an unnamed official as saying. “The kingdom’s economy has an influential and vital role in the global economy”.  The response underlines the mounting international pressure on Saudi Arabia and its de facto ruler Crown Prince Mohammed bin Salman since Mr Khashoggi disappeared after entering its consulate in Istanbul earlier this month. Turkish officials have said they believe the journalist, who is a US resident, was killed inside the consulate.

Mevlut Cavusoglu, Turkey’s foreign minister, said Saudi Arabia had not co-operated in the investigation, despite proposing to create a “joint working group” with Turkish authorities. In an unusual move for countries that have tended to prioritise bilateral ties with Riyadh, Britain, France and Germany issued a joint statement saying they were treating the incident “with the utmost seriousness” and “expect the Saudi government to provide a complete and detailed response”.

The Saudi stock market plunged as much as 7 per cent on Sunday before closing down 3.5 per cent.  Riyadh has repeatedly denied any involvement. But the case of Mr Khashoggi, who wrote a regular column for the Washington Post and was critical of Saudi authorities, threatens to trigger the biggest diplomatic dispute with its western allies in years.