The European Union's top diplomat demanded on Thursday that the Houthis cease attacks on ships in the Red Sea, after a Saudi vessel was hit by the Iran-backed rebels.
"The attack on an oil tanker in the Red Sea is unacceptable, illegal and further inflames an already volatile situation in the region," EU foreign policy chief Kaja Kallas said in a statement.
"The Houthis must cease all actions that endanger international shipping and the lives of seafarers."
The attack on Saudi shipping in the Red Sea brought the war in the Middle East to a new front and sent oil prices surging.
Earlier this week, the Houthis said they had struck two Saudi oil tankers after declaring a blockade of Saudi ports.
Kallas said an EU naval mission deployed in the Red Sea to help ships pass through the vital waterway "remains firmly committed to protecting freedom of navigation for all".
Meanwhile, United States President Donald Trump on Thursday threatened Yemen's Houthi rebels with "major military punishment" after the attack on the oil tankers.
"The US will hold Iran responsible, in that the Houthis are a surrogate and/or proxy of Iran, and major military punishment will be inflicted upon Iran and, of course, the Houthis themselves," Trump posted on his Truth Social network.
The Houthis are an armed movement from Yemen’s Zaydi Shia community that took control of Sanaa in 2014.
Since then, they have held sway over much of northern Yemen and have become closely associated with Iran, which Western governments accuse of backing the group militarily and politically.
The Houthis reject the label of Iranian proxy.
(with newswires)
