By Stephen Kalin
RIYADH, Sept 16 (Reuters) - Saudi Arabia said on Monday thatthe attack on its oil facilities was carried out with Iranianweapons, according to a preliminary investigation, but stoppedshort of directly blaming regional foe Iran.
A foreign ministry statement said Riyadh would inviteinternational experts, including from the United Nations, toparticipate in investigating Saturday's assault, which cutalmost half of Saudi Arabia's oil production.
The United States, which has blamed Iran for the strikes, isstudying all available options in addressing the assault, U.S.Defense Secretary Mark Esper told Saudi Crown Prince Mohammedbin Salman in a phone call on Monday, Saudi state media said.
"Initial investigations show that Iranian weapons were usedin the attacks and work is going on to determine the source ofthose attacks," the foreign ministry statement said.
"The kingdom is capable of defending its land and people andresponding forcefully to those attacks," it added.
Yemen's Iran-aligned Houthi movement has claimedresponsibility for the strikes, but the spokesman for theSaudi-led military coalition battling the group said preliminaryfindings indicated the attack was not launched from Yemen.
Tehran has dismissed the U.S. accusations as "unacceptable"and said it was ready for a "full-fledged war."
Riyadh called on the world to condemn those behind theattack on the world's top oil exporter, a key regional U.S. allywhich has supported U.S. President Donald Trump's"maximum-pressure" campaign on Shi'ite Muslim Iran.
Prince Mohammed, Saudi Arabia's de facto ruler, told Esperthat Iranian threats "are not only directed to the kingdom, butaffect the Middle East and the world," news agency SPA said.
Pakistan Prime Minister Imran Khan, who also called thecrown prince on Monday, offered his country's "full support andcapabilities" to the Gulf Arab state, it added.
The Wall Street Journal reported that U.S. officials hadsaid intelligence indicated Iran was the "staging ground" forthe attack and had shared the information with Riyadh. It quotedpeople familiar with the discussions.
Coalition spokesman Colonel Turki al-Malki told reporters inRiyadh earlier on Monday that authorities were still determiningthe launch location.
"The terrorist attack did not originate from Yemen as theHouthi militia claimed," he said, adding that authorities wouldreveal the location from where drones were launched at a futurenews conference.
The Saudi-led coalition of Sunni Muslim countries intervenedin Yemen in March 2015 against the Houthis, who ousted theinternationally recognized government from power in the capitalSanaa, to prevent Iran from gaining influence through the group.
The movement, which denies being a puppet of Tehran and saysit is fighting a corrupt system, recently stepped up drone andmissile attacks on Saudi cities. The conflict is largely seen inthe region as a proxy war between Saudi Arabia and Iran.(Reporting by Stephen Kalin in Riyadh; Additional reporting bySamar Hassan in Cairo, Eric Knecht in Doha and Maher Chmaytelliin Dubai; Writing by Ghaida Ghantous, William Maclean; Editingby Andrew Cawthorne and Jonathan Oatis)