U.S. Markets open in 2 hrs 56 mins

UPDATE 1-UK's Johnson and Trump discuss need for united diplomatic response to Saudi attack

(Adds White House statement)

LONDON, Sept 18 (Reuters) - British Prime Minister Boris Johnson and U.S. President Donald Trump condemned last weekend's attack on Saudi Arabian oil facilities and discussed the need for a united diplomatic response in a telephone call on Wednesday, Johnson's office said.

"They condemned the attacks and discussed the need for a united diplomatic response from international partners," a statement said. "They also spoke about Iran and agreed that they must not be allowed to obtain a nuclear weapon."

A White House spokesman said in a statement the two leaders "reaffirmed the value of the special relationship in addressing shared security concerns, most notably Iran's destabilizing behavior". (Reporting by Stephen Addison; Additional reporting by Mohammad Zargham in Washington; editing by David Milliken)