Sources familiar with the meeting said earlier that Hook, a senior policy adviser to U.S. Secretary of State Mike Pompeo, had spoken with Falih a day before the Organization of the Petroleum Exporting Countries was due to debate oil output cuts.
The United States reimposed sanctions on OPEC member Iran last month. The measure has severely reduced Iranian oil flows. Washington has said it wants ultimately to drive Iranian shipments to zero.
A Saudi Energy Ministry spokesman said of the talks between Falih and Hook: "We categorically deny such a meeting took place." However, a U.S. State Department spokeswoman later confirmed the meeting occurred.
"Special Representative for Iran Brian Hook met briefly with the Saudi Minister of Energy in Vienna on Wednesday," the State Department spokeswoman said.
U.S. President Donald Trump has urged Saudi Arabia, OPEC's de facto leader, to refrain from production cuts in order to keep oil prices low. He said higher oil supplies were a payback from Riyadh for U.S. support against Saudi arch-rival Iran.
Iran's Oil Minister Bijan Zanganeh criticised Hook over the meeting for what he said was his "meddlesome approach".
"If Mr. Hook has come to Vienna to apply for U.S. membership in OPEC, and this is the reason why he meets OPEC members, this request shall be reviewed,” Zanganeh told Iran's Oil Ministry news website SHANA.
"Otherwise, he has adopted an unprofessional, naive and meddlesome approach. OPEC is an independent organisation and is not part of the U.S. Department of Energy to take orders from Washington," Zanganeh told SHANA.
(Reporting by Rania El Gamal; additional reporting by Mohamed El-Sherif in Cairo and Arshad Mohammed in Washington; writing and editing by Dmitry Zhdannikov, Dale Hudson and Dubai newsroom; Editing by Dale Hudson and Edmund Blair)
(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)