Iran must "end its arming of and support" for the Houthis in Yemen, the foreign ministers of G7 nations have said in a joint statement.
The G7 also condemned "in the strongest terms" Houthi attacks on Saudi Arabia, adding that the recent escalation in fighting against Saudi-backed forces in Yemen represented a threat to regional and global energy security.
Thousands of refugees have fled Yemen in recent days after the Iran-backed group seized territory along the country's Red Sea coastline, including near the Bab al-Mandab Strait, a critical shipping route for global trade.
The statement comes ahead of the annual UN General Assembly in New York, where senior Iranian officials are due to speak.
"We call on the Houthis to immediately cease all military actions, all threats and attacks against civilian shipping, and to return to the political process in good faith," said the foreign ministers of the UK, Canada, France, Germany, Italy, Japan and the United States.
Their statement was issued following a meeting on the sidelines of the UN General Assembly.
Meanwhile, at least six people were killed in Saudi strikes on the strategic Yemeni city of Mokha, the AFP news agency reported, citing Houthi-affiliated media.
Two children and a woman were among the dead, while eight others were injured in the attack on the city, which the Houthis seized from pro-government forces earlier this month.
Saudi Arabia, which backs the internationally recognised government of Yemen, has not yet commented on the reported strikes.
The UN estimates that in all, more than 120,000 Yemenis have been displaced by the sudden surge in fighting along Yemen's Red Sea coast.
Earlier this month, the Houthis, who had already seized most of the populated parts of Yemen, took control of Bab al-Mandab, a narrow, maritime chokepoint where the southern Red Sea flows into the Gulf of Aden and the wider Indian Ocean.
Saudi Arabia has retaliated with hundreds of air strikes in the region.
The Houthis have also launched hundreds of drones and missiles at cities and infrastructure in south-western Saudi Arabia, including the capital city, Riyadh.
Prime Minister Andy Burnham has said the UK will provide "defensive air-to-air refuelling" support for Saudi Arabia, involving a single British aircraft, a Voyager, based out of RAF Akrotiri in Cyprus.
Burnham said the announcement followed a request from Saudi Arabia for "military support", which he agreed to on the advice of Defence Secretary Wes Streeting and Foreign Secretary Ed Miliband.
Saudi Crown Prince Mohammed bin Salman has also requested military support from President Donald Trump, US media reported.
Trump has wavered for weeks over whether to act on a Saudi request for help in fighting the Houthis, the New York Times reported on Monday.
The US president had earlier told Fox News that he was in "deciding mode" as he considered options for the next steps in the war against Iran.
On Sunday, US embassies across the Middle East issued new security alerts as fighting between the Houthis and the Saudi-backed coalition in Yemen intensified.
The Houthis declare themselves to be part of the Iranian-led "axis of resistance" against Israel, the US and the wider West - along with armed group such as Hamas and Lebanon's Hezbollah movement.
Tehran has previously denied supplying weapons to the Houthis and says it only supports them politically.
