The United Nations said more than 350,000 people have been displaced from the strategic Red Sea port town of Hudaydah in western Yemen since June.
Deputy spokesman for the Secretary-General, Farhan Haq, said during a press conference on Monday that violent clashes have erupted in the city over the past few days, especially in the Ad Durayhimi district.
He added that emergency humanitarian assistance has already been provided to more than 90 per cent of those displaced.
Yemeni government forces last week launched an attack against Houthi fighters in the centre of Ad Durayhimi district after fighting calmed in Hudaydah in mid-June to allow negotiations led by the United Nations envoy for Yemen, Martin Griffiths, to take place.
A Saudi-led Arab coalition, which joined the war in 2015 to support the internationally backed President Abd Rabbuh Mansur Hadi, and the Yemeni government have repeatedly called on the Houthis to withdraw from the strategic port town of Hudaydah.