"Britain is undoubtedly... responsible for war crimes committed in Yemen over the past three years by selling weapons, providing logistic and intelligence assistance to the aggressor countries, and helping (to impose) an inhuman blockade on the people of the country", Qassemi said in a statement on Monday.
The spokesperson for the coalition forces fighting to restore legitimacy in Yemen Col.
Iran's Revolutionary Guards on Tuesday denied Saudi Arabian accusations that Tehran provided the Houthi rebels in Yemen with ballistic capabilities, a day after Saudi Arabia threatened retaliation against the Islamic Republic for a barrage of missiles fired by Houthi rebels from Yemen.
He claimed that an Iranian-made missile with Persian writing was confiscated in Yemen, and a shipment of missiles from Iran haی been seized before they were used by Houthi fighters.
"On the other hand, by making such claims, Saudi Arabia seeks to cover up its failures in Yemen", he noted.
Saudi rulers were expected at least to learn their lesson from the military aggression against the Yemeni people and give up their "delusion of grandiosity" and also to realize that they "cannot generate power and security by relying on arms purchases and costly and imported security", he pointed out.
Another diplomat said discussions in European Union capitals were moving in favour of new sanctions, partly after ballistic missiles fired by Yemen's Iran-backed Houthi militia killed a man in Riyadh on Sunday.
The study by Conflict Armament Research comes as the West and United Nations researchers identified Iran as supplying arms to Yemen's Houthis, a Shiite rebel group which has held the country's capital since September 2014.
Seventy eight percent of 104 ballistic missiles that have been launched on Saudi Arabia, including Mecca and Riyadh, come from Yemen's Saadah and north of Amran, said Maliki.
Britain is the third largest humanitarian donor to Yemen. The statement urged the U.S. and European countries to stop supporting "aggressors" by providing weapons and jets.
Over 14,000 Yemenis, including thousands of women and children, have lost their lives in the deadly military campaign.