US Secretary of State Mike Pompeo blamed Iran for a Saturday attack on Saudi oil facilities.
"Tehran is behind nearly 100 attacks on Saudi Arabia while Rouhani and Zarif pretend to engage in diplomacy," Pompeo tweeted Saturday. "Amid all the calls for de-escalation, Iran has now launched an unprecedented attack on the world’s energy supply. There is no evidence the attacks came from Yemen."
"We call on all nations to publicly and unequivocally condemn Iran’s attacks. The United States will work with our partners and allies to ensure that energy markets remain well supplied and Iran is held accountable for its aggression."
Earlier on Saturday, reports claimed Yemenite Houthis had perpetrated the drone attacks, which harmed two Saudi oil facilities, one of which is the world's largest.
CNN quoted the Houthi-run Al-Masirah news agency, which said the Houthis had claimed responsibility for the attacks, which used 10 drones to target state-owned Saudi Aramco facilities in Abqaiq and Khurais.
The attacks impacted five million barrels of crude oil per day, effectively forcing Saudi Arabia to cut its crude oil production by half.
The kingdom has said it hopes to have production back to normal within ten days.
Meanwhile, Iran on Saturday signed a $440 million contract to open an oil field in the Gulf, under which Petropars, a local company, will work with Iran to develop the Belal gas field to develop 500 million cubic feet of gas per day, Reuters reported.
Iranian Oil Minister Bijan Zanganeh said: "This contract and other upcoming contracts show that we are working under the sanctions. The sanctions have not stopped us and we are active."