Washington - US President Donald Trump said on Wednesday he had ordered Treasury Secretary Steven Mnuchin to “substantially increase sanctions” imposed on Iran, amid escalating tensions between Washington and Tehran.

He did not give additional details on the move, which follows weekend attacks on oil facilities in Saudi Arabia that some US officials have blamed on Iran.

Saudi Arabia said it would produce evidence on Wednesday linking regional rival Tehran to an unprecedented attack on its oil industry that Washington believes originated from Iran in a dangerous escalation of Middle East frictions.