Iran accused Britain of hypocrisy on Monday for saying it should stop supplying weapons to Yemeni rebels.
"Britain undoubtedly has direct responsibility for the war crimes committed over the past three years in Yemen by selling arms and providing logistical and intelligence support to the countries attacking Yemen," said foreign ministry spokesman Bahram Ghasemi on the ministry's website.
"This country is in no position to accuse other countries and it would be better for it to end as soon as possible its opportunistic and profiteering approach to this blind war," he added.
Saudi Arabia has been engaged for the past three years in an aerial bombing campaign against Yemen's Huthi rebels, who it says are being supplied by Iran.
Tehran has repeatedly denied the allegations, but Riyadh again accused Iran of supplying the seven missiles that were fired by the Huthis into Saudi territory on Sunday, killing one person.
British Foreign Secretary Boris Johnson and International Development Secretary Penny Mordaunt on Monday called on Iran to "stop sending in weapons which prolong the conflict, fuel regional tensions, and pose threats to international peace and security."
Britain and the US have supplied billions of dollars' worth of arms to Saudi Arabia in recent years.
London is close to signing another multi-billion-dollar deal to supply Typhoon fighter jets to Riyadh.
"If Britain is honest in its claim to want a political solution to the crisis in Yemen, it would be better to ask those large buyers of British weapons in the war coalition against Yemen to stop the conflict and end the siege of the oppressed people of that country," said Ghasemi.
On Friday, Amnesty International said all parties in the conflict were guilty of neglecting civilian safety.
But it said the Saudi-led coalition -- armed by the US and Britain -- may be guilty of war crimes.
"There is extensive evidence that irresponsible arms flows to the Saudi Arabia-led coalition have resulted in enormous harm to Yemeni civilians," said Lynn Maalouf, head of Middle East research at Amnesty.