President Donald Trump targeted Supreme Leader Ayatollah Ali Khamenei and other top officials with sanctions on Monday and Tehran said the sanctions imposed on its top officials permanently closed the path to diplomacy between the countries.

A U.S. official also said on Monday that Trump was "comfortable with any outcome" from talks with Chinese President Xi Jinping at the meetings beginning on Friday.

The resulting anxiety on global markets weakened Asian stocks and sent investors scurrying for the traditional security of gold, the Swiss franc and the yen.

The pan-European STOXX 600 index fell 0.3% by 0710 GMT, with the technology sector bucking the trend on the back of Capgemini's purchase of engineering and digital services company Altran for 3.6 billion euros ($4.10 billion).

Capgemini shares rose 7% and those in rival SAP SE 0.3%, pushing the sector around half a percent higher, while Altran surged 21%.