Saudi, Emirati, and Yemeni government forces have launched a fresh offensive to retake the Houthi-held city of Hodeidah in the west of Yemen.
The alliance claimed to have captured two areas on the outskirts of the city after the advance began on Tuesday morning.
UAE state news agency WAM reported that the military alliance launched a "large-scale" offensive to retake Hodeidah, with Yemeni ground forces capturing the Kilo 7 and Kilo 10 areas which sit less than 5km from the city's busy fish market.
The rebel-run Al Masirah TV network said air raids hit a navy school and residents reported air raids targeting Houthi positions in and around the city of 600,000.
"[Yemeni] forces are strengthening their presence in Kilo 16 which cuts supply lines for the Houthis between Sanaa and Hodeidah," said Ali al-Taniji, commander of the forces fighting on Yemen's west coast.
Fighting near Hodeidah - the main gateway for imports of relief supplies and commercial goods into the country - has escalated since June 13 after the Saudi-UAE alliance launched a wide-ranging operation to retake the strategic seaport.
The offensive is being carried out by a disparate collective of forces including the National Resistance, a group of fighters loyal to Yemen's former President Ali Abdullah Saleh, the Tihama Resistance, a group of fighters loyal to Yemen's President Abd-Rabbu Mansour Hadi, and the Giant Brigades, a military unit backed by the United Arab Emirates.
Riyadh and Abu Dhabi see Hodeidah port as the main entry point of weapons for the Houthis and have accused their regional rival Iran of sending missiles to the rebels, a charge Tehran has denied.
Lifeline for millions
Aid agencies have warned an assault on Hodeidah could shut down one of the last remaining lifelines for millions of hungry civilians, with the UN scrambling to mediate between the warring sides.
The UN special envoy for Yemen, Martin Griffiths, arrived in Sanaa to meet with the Houthis on Sunday, and on Monday, a spokesman for the rebels wrote on Twitter that Griffiths met the group's leader, Abdul Malik al-Houthi.
Mohammed Abdul Salam said discussions focused on the humanitarian situation in the country and plans for future consultations between the two sides.
Fighting in Hodeidah risks escalating the dire humanitarian crisis in the country, where out of a population of 28 million people, eight million - a number greater than the entire population of Switzerland- are on the verge of famine.
On Saturday, the Houthis signed a memorandum of understanding with the UN to allow the transport of critically ill patients abroad for treatment over a period of six months.
The World Health Organization (WHO) said 12 health conditions had been identified as qualifying for transport, including cancer, chronic diseases, and congenital anomalies.
The war in Yemen, the region's poorest country, started in 2014 when the Houthis overran much of the country, including Sanaa.
Hadi's government was toppled by Houthi rebels in late 2014 after the rebels advanced south from their stronghold of Saada and captured large parts of the north.
The conflict escalated in 2015 when Saudi Arabia and the UAE launched air raids in an attempt to reinstate the internationally recognised government of President Abu-Rabbu Mansour Hadi.
With logistical support from the US, the Saudi-UAE alliance has carried out more than 16,000 raids on Houthi-held areas in an attempt to reverse their gains.
These attacks have targeted weddings and hospitals as well as water and electricity plants, killing and wounding thousands.