Tehran wants an “endless war” in Yemen, the US special envoy to Iran said on Wednesday as he lobbied leaders in London to back an extension to the UN Security Council’s arms embargo on Iran.

Brian Hook said a EU embargo that expires in 2023 was insufficient.

The Security Council restrictions are set to end in October but the US has proposed extending it indefinitely.

The move is unlikely to pass because Russia and China, which have the power of veto in the council, have indicated their opposition.

“Nobody believes that Iran should be able to buy or sell conventional weapons like fighter jets, battle tanks, large-calibre artillery systems, warships and various kinds of missiles,” Mr Hook told a briefing in London, The Guardian reported.

“Iran would like to see endless war on Saudi Arabia’s southern flank in Yemen."

Iran continues to back the Houthi rebels in Yemen.

Mr Hook said the region would be more unstable if the arms embargo were allowed to expire and freedom of navigation in the Arabian Gulf would be under greater threat.

“It’s great that Europe has these sanctions in place but what we need is a global embargo, and if you do not have a global embargo it allows Iran to purchase these weapons,” he said.

“The question in front of the international community is not whether the international arms embargo should be extended, but how and when.”

Tension between Tehran and Washington have increased since US President Donald Trump came to power.

Mr Trump withdrew from a 2015 deal between Tehran and world powers to limit Iranian nuclear ambitions, and reimposed sanctions on Iran.