Iran on Sunday accused the United States of responsibility for "atrocities" in Yemen through its support for Saudi Arabia, which is leading a coalition fighting Tehran-backed Houthi rebels.
Iran's foreign ministry spokesman Bahram Ghassemi said a White House statement on Friday in support of Riyadh "clearly and without question proves America's participation and responsibility in the atrocities committed by Saudi Arabia in Yemen".
In its statement, Washington had said it was "committed to supporting Saudi Arabia... against the Iranian Islamic Revolutionary Guard Corps' aggression and blatant violations of international law."
Regional arch-rivals Shia-ruled Iran and Sunni heavyweight Saudi Arabia back opposing sides in conflicts from Yemen to Syria.
They cut diplomatic relations in January 2016 after Iranian protestors stormed Saudi diplomatic missions in reaction to Riyadh's execution of a prominent Shiite cleric.
In early November, Riyadh accused Tehran of "direct aggression" after Saudi forces intercepted a missile fired by Houthi forces towards Riyadh's international airport.
But Ghassemi denied that Iran has "any military connection with Yemen", although Tehran says it supports the Houthis politically and regularly denounces Saudi Arabia for allegedly bombing civilians.
Accusing Washington of making "totally unfounded" allegations, Ghassemi said its statement on Friday showed it "openly supports... appalling atrocities" by Saudi Arabia in Yemen.