The United Nations is extremely concerned by a Yemen military offensive to seize the port of Hodeida and has begun drawing up plans to deal with a possible escalation in fighting, the UN spokesman said on Tuesday.
Yemen's government forces, backed by the Saudi-led coalition, were closing in on the rebel-held Red Sea port, which is a key entry point for humanitarian aid.
The coalition has accused Yemen's Houthi rebels of using the port to smuggle weapons that have been fueling the war.
"We are extremely concerned about the situation around Hodeida," said UN spokesman Stephane Dujarric, adding that UN staff were drawing up contingency plans and stepping up aid deliveries.
UN officials in Yemen and the region have "already started to take precautionary measures in terms of ramping up assistance and redefining contingency plans in case there is further escalation," he said.
Food and other items have been delivered to displaced families.
"Increased fighting would unleash even more internally displaced people," he said.
More than 22 million people in Yemen are in need of aid including 8.4 million who are at risk of starvation, according to the United Nations which considers Yemen to be the world's worst humanitarian crisis.
Since 2015, Saudi Arabia has been leading a military campaign to push back the Huthis and restore the internationally recognised government to power.
The conflict has left nearly 10,000 people dead, tens of thousands wounded in what was already the Arab world's poorest country.
