A Downing St spokesperson said:
King Salman of Saudi Arabia called the Prime Minister last night to congratulate her on her appointment.
The Prime Minister thanked the King for his call and offered her condolences for the recent terrorist attacks there. The PM said the UK stood shoulder to shoulder with Saudi Arabia in the fight against violent extremism and terrorism.
Both agreed that the United Kingdom and Saudi Arabia share a long-standing, strong bilateral relationship and they expressed their firm commitment to strengthening co-operation further, particularly on counter-terrorism, security, defence and trade.