The U.S., the European Union, NATO and several countries, including the internationally recognized Yemeni government, issued a joint statement on Tuesday condemning "Houthi interference with navigational rights and freedoms" amid attacks in the Red Sea.

"The undersigned further encourage all states to refrain from facilitation or encouragement of the Houthis. There is no justification for these attacks, which affect many countries beyond the flags these ships sail under," the signatories to the statement said.

A UN spokesperson said the UN also condemns Houthi attacks against international shipping lanes in the Red Sea.

"It is not only impeding the freedom of navigation, which is an important part of international law," said Stephane Dujarric, adding that it has "the potential of creating havoc" on global trade. The spokesperson also warned of a potential ecological disaster if a full tanker explodes in the sea.

The Red Sea is one of the world's most frequently used sea routes for oil and fuel shipments.

Yemen's Ansar Allah, also called the Houthis, has significantly stepped up its involvement in the current conflict in the Gaza Strip by targeting vessels in the southern Red Sea. The group, which is purportedly backed by Iran, has threatened to attack all Israel-bound ships, saying the attacks aim to support Palestinians as they face Israel's "aggression and siege" in Gaza.

The U.S. on Tuesday launched a multinational operation to safeguard commerce in the Red Sea as attacks by the Houthis forced major shipping companies to reroute, fueling concern over sustained disruptions to global trade.

"The international coalition that America announced under the pretext of protecting maritime navigation in the Red Sea is an alliance to protect the Israeli entity and to protect Israeli ships. It is an integral part of the aggression against the Palestinian people, Gaza, and the Arab and Islamic nations," said the statement issued by the political bureau of the Houthis.

"Yemen's armed forces don't represent any threat to any country; we only target Israeli ships or ships heading toward Israeli ports," it added.

"We affirm our steadfast position in supporting the Palestinian people until Israel's aggression ends and (the) siege on the Gaza strip is lifted."

Senior Houthi official Mohammed al-Bukhaiti wrote on social media that the rebels would only halt their attacks if Israel's "crimes in Gaza stop and food, medicines and fuel are allowed to reach its besieged population."

Companies rush to avert disruption, shipping rates rise

Global shipping rates rose sharply, and companies scrambled to avoid disruptions to shipments after attacks on vessels in the Red Sea stymied traffic through the key Suez Canal trade artery.

Recent attacks on vessels forced leading shipping companies, including Maersk, to reroute around the Cape of Good Hope to avoid the Suez Canal, the shortest shipping route between Europe and Asia.

The attacks have stirred memories of 2021, when container ship Ever Given ran aground in the canal, blocking dozens of container ships for six days. The current disruption has caused container shipping costs to rise sharply.

As of Tuesday, the price to ship a container from China to the Mediterranean was $2,413, having risen 44 percent in December due to the disruptions after hitting a low of $1,371 earlier this year, said Eytan Buchman, chief marketing officer at Freightos, a booking and payments platform for international freight.

The longer journey will cost up to $1 million extra in fuel for every round trip between Asia and Northern Europe, according to estimates from freight platform Xeneta.

Delays to shipments will not affect Christmas holiday shopping, but there is the potential for shops to run low on stock by February if the delays continue, supply chain research firm Project44 said in a note on Tuesday.

"After the peak shopping season through the holidays, it is possible that inventories will be depleted," it said.

(With input from agencies)