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RIYADH, Sept 16 (Reuters) - The Saudi-led military coalition battling Yemen's Houthi movement said on Monday that the attack on Saudi Arabian oil plants was carried out with Iranian weapons and was not launched from Yemen according to preliminary findings.

Coalition spokesman Colonel Turki al-Malki said that an investigation into Saturday's strikes, which had been claimed by the Iran-aligned Houthi group, was still going on to determine the launch location.

"The preliminary results show that the weapons are Iranian and we are currently working to determine the location ... The terrorist attack did not originate from Yemen as the Houthi militia claimed," Malki told a press conference in Riyadh.

He said authorities would reveal the location from where drones were launched at a future press briefing.

Iran has dismissed as "unacceptable" U.S. accusations that Tehran was responsible for the assault on Saudi oil facilities that cut almost half of the kingdom's production, or 5% of global oil supply.

Malki said the Gulf Arab state, the world's top oil exporter, was capable of protecting vital energy and economic sites. "This cowardly act largely targets the global economy and not Saudi Arabia."

The Western-backed, Sunni Muslim alliance intervened in Yemen in March 2015 to try to restore the internationally recognised government ousted from power in the capital Sanaa in late 2014 by the Houthis.

The movement has stepped up drone and missile attacks on Saudi cities this year. The conflict is largely seen in the region as a proxy war between Saudi Arabia and Iran. (Reporting by Stephen Kalin in Riyadh and Maher Chmaytelli in Dubai; Writing by Ghaida Ghantous, William Maclean)

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