Clashes between Yemen's Houthi rebels and a government alliance led by the United Arab Emirates broke out near the Red Sea city of Hodeida on Friday, military sources said.
The violence came as United Nations-sponsored peace talks in Geneva have failed to get off the ground, with the Houthi delegation refusing to leave Yemen over alleged fears it will be blocked from returning to the capital Sanaa.
Multiple military sources reported the government alliance attempted on Friday to close in on rebel-held Hodeida, a city home to impoverished Yemen's most valuable port.
The coalition, which launched an offensive on Hodeida in June, advanced some 16 kilometres along the coastal road of the al-Durayhmi district on Friday, a military source said.
The road is a key supply route for the rebels, who still hold Hodeida city.
The fate of embattled Hodeida was scheduled for discussion at the Geneva conference, originally due to open on Thursday but now on hold until an agreement is reached with the rebels.
The Iran-aligned Houthis have demanded the UN guarantee their delegation's safe return to Sanaa and allow the evacuation of wounded rebels from the capital to nearby Oman.
The rebels seized control of Sanaa in 2014 along with the Red Sea Hodeida port.
Hodeida's port serves as an entry point for some 70% of imports in a country where eight million people face imminent famine.
The government and the Saudi-led coalition that backs it accuse the Houthis of receiving smuggled weapons through Hodeida and have demanded their unconditional withdrawal from the city.
Government forces backed by the coalition have paused their assault on Hodeida port in what they say is a bid to give UN-led peace efforts a chance, but clashes have erupted sporadically.
Nearly 10,000 people have been killed in the Yemen conflict since 2015, when the Saudi-led alliance intervened in the civil conflict between the government and rebels.