At least 120 fighters from both sides have been killed in clashes between the Iran-backed Houthi movement and Saudi-backed government forces, according to sources who told AFP.
A Houthi source told Al Jazeera that more than 100 people have been killed in the past 48 hours.
The fighting began when the Houthis launched an attack with ground forces, rockets and drones south of Houthi-controlled al-Hudaydah, targeting the government-controlled coastal city of Mocha.
The warring sides are competing for control of the Bab al-Mandab Strait, the southern gateway to the Red Sea, which has become an increasingly important shipping lane since the Iran war cut off traffic in the Strait of Hormuz.
A fragile ceasefire between the Houthi movement and Yemen's government collapsed in July. The country's civil war has been going on for more than a decade.
