Russia and China on Wednesday accused the United States and Britain of illegally attacking military sites used by Yemen’s Houthi rebels to launch missiles at commercial vessels in the Red Sea, disrupting global shipping.

US deputy ambassador Robert Wood and UK Ambassador Barbara Woodward countered that the Houthi attacks are illegal, and their “proportionate and legal action” against the Yemen rebels are being taken in self-defense.Woodward said the Houthi attacks are “driving up the costs of global shipping, including the costs of food supplies and humanitarian aid in the region.” But Russia’s deputy U.N. ambassador Dmitry Polyansky and China’s UN envoy Zhang Jun argued that the U.N. Security Council never authorized military action against Yemen.The clashes came at a council meeting where UN special envoy for Yemen Hans Grundberg said promising efforts to restore peace to Yemen have been slowed by rising regional tensions linked to the war in Gaza and “in particular the military escalation in the Red Sea.”

Since November, the Houthi rebels have targeted ships in the Red Sea to demand a cease-fire in Israel’s offensive in Gaza.

They have frequently attacked vessels with tenuous or no clear links to Israel, imperiling shipping in a key route for trade among Asia, the Mideast and Europe.

In recent weeks, the United States and the United Kingdom, backed by other allies, have launched airstrikes targeting Houthi missile arsenals and launch sites for its attacks.

Wood, the . envoy, said American strikes in response to attacks on US naval US vessels, “aim to disrupt and degrade the Houthis’ ability to continue their reckless attacks against vessels and commercial shipping in the Red Sea, the Bab al-Mandeb Strait, and the Gulf of Aden.”

Since 2014, he said, Iran has provided the Houthis with “a growing arsenal of advanced weapons” that they have used to target commercial ships, and “Iran cannot deny its role in enabling and supporting the attacks carried out by the Houthis.” Wood accused the Houthis of “trying to apply a chokehold on global shipping through the Red Sea” and urged all countries, especially those with direct channels to Iran, “to press Iran’s leaders to rein in the Houthis and stop these lawless attacks.”

Russia’s Polyansky stressed that Moscow “categorically condemns attacks and seizures of commercial vessels and (...) any attacks which impede freedom of navigation.”

He said Russia has conveyed messages to the Houthi leaders to focus on Yemen’s domestic agenda and pursue peace.