DOHA - U.S. Treasury Secretary Steven Mnuchin said on Saturday U.S. troops were in Saudi Arabia on a defensive basis only and that the United States would end all sanctions on Iran when Tehran fulfilled necessary conditions.

Mnuchin also told the Doha Forum conference that attacks on Saudi oil facilities, which the United States has blamed on Iran and Tehran has denied - were attacks on the world's economy.

(Reporting by Dmitry Zhdannikov and Alrexander Cornwell Writing by Aziz El Yaakoubi Editing by Mark Heinrich) ((aziz.elyaakoubi@thomsonreuters.com; +971552994086; Reuters Messaging: aziz.elyaakoubi.reuters.com@reuters.net))