Yemeni forces backed by a Saudi-led coalition say they have captured the airport of the main port city of Hudaydah from Houthi rebels.
The military said engineers were now checking the surrounding area for mines. The Houthis have not acknowledged losing the airport.
There has been no fighting in the city centre or port, seen as a lifeline for millions of Yemenis at risk of famine.
Hudaydah is the only major port controlled by the Houthis.
UN special envoy Martin Griffiths arrived in the capital Sanaa on Saturday for emergency talks on the situation at the port, AFP reported.
He is expected to propose to the Houthis, who control Sanaa, that they cede control of Hudaydah to a UN-supervised committee to avoid further fighting.
The Hudaydah offensive, which is being directed by the United Arab Emirates, began on Wednesday.
Meanwhile UAE military sources say a major force of Yemeni, UAE and Sudanese troops is on standby in Eritrea to take part in a final effort to capture Hudaydah.
Quoted by Reuters, the media office of the Yemeni military said on Twitter: “Army forces backed by the resistance and the Arab alliance freed Hudaydah international airport from the grip of the Houthi militia.”
Yemen has been devastated by a conflict that escalated in early 2015, when the Houthis seized control of much of the west of the country, including the capital Sanaa, and forced President Abdrabbuh Mansour Hadi to flee abroad.
Alarmed by the rise of a group they saw as an Iranian proxy, Saudi Arabia and eight other Arab states intervened in an attempt to restore Mr Hadi’s government.
Almost 10,000 people – two-thirds of them civilians – have been killed and 55,000 others injured in the fighting, according to the United Nations.
The conflict and a partial blockade by the coalition have also left 22 million people in need of humanitarian aid, created the world’s largest food emergency, and led to a cholera outbreak that is thought to have killed 2,290 people.