The two leaders also agreed on the need to reduce the escalation in the region and expressed their commitment to a common approach to Iran, which US President Donald Trump has blamed for the attack, the spokesman said.
"Blatant violation of international law"
Johnson said Monday that attacks on Saudi oil facilities were a flagrant violation of international law.
British Foreign Secretary Dominique Rapp said the attack was "dangerous and outrageous. "It is a blatant violation of international law," he said "The picture is not very clear with regard to the perpetrators ... I want to have a very clear picture, which will happen soon."
"This attack has implications for global oil markets and supplies," he said. "It is a very dangerous and outrageous act, and we must have a clear and unified international response to its fullest extent."