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."
Iran and saudi arabia cut diplomatic relations in January 2016 after Riyadh's execution of a prominent Shia cleric.
Ghasemi said US statement on Friday is making "totally unfounded" allegations, showed its "openly supports... appalling atrocities" by Saudi Arabia in Yemen.