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 Shiite-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 Huthi forces towards Riyadh's international airport.
But Ghassemi denied that Iran has "any military connection with Yemen", although Tehran says it supports the Huthis 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.
The Saudi-led Arab military coalition intervened in Yemen in March 2015 to support President Abedrabbo Mansour Hadi after the Huthis forced him into exile.
Last month, the United Nations put the coalition on its blacklist for killing and maiming 683 children during the conflict last year and carrying out 38 verified attacks on schools and hospitals.
A report published in mid-November by the Congressional Research Service showed that Riyadh had signed arms deals worth more than $65 billion (55 billion euros) with the United States between 2009 and 2016.
"Since 2015, the US-trained Saudi military has used US-origin weaponry, US logistical assistance, and shared intelligence in support of military operations in Yemen," it said.
Both parties in the Yemen conflict stand accused of neglecting civilian safety.
The United Nations has blacklisted the Saudi-led coalition over the "killing and maiming" of children.
Eyewitness? Submit your stories now via social or:
Email: eyewitness@pulse.ng
![33 passengers and one crew member died on the dive boat, Conception [Brian van der Brug/Los Angeles Times/AP]](data:image/svg+xml;charset=utf8,%3Csvg%20xmlns%3D'http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg'%20width%3D'300'%20height%3D'172'%20data-ring-placeholder%3D'1'%3E%3C%2Fsvg%3E "33 passengers and one crew member died on the dive boat, Conception [Brian van der Brug/Los Angeles Times/AP]")
