Yemen's rebel chief vowed on Wednesday he would never surrender to Saudi-backed pro-government forces, as international aid groups appealed for safe passage for civilians caught in the flashpoint port of Hodeida.
After six days of intense battles, pro-government forces on Wednesday pressed even closer to the heart of Hodeida, the Red Sea city controlled by the Houthi rebels and under blockade by Saudi Arabia and its allies.
Plumes of smoke were seen billowing from the horizon on Tuesday as heavily armed pro-government forces moved towards the port on foot and on the back of pickup trucks.
The coalition, an alliance led by Saudi Arabia and the United Arab Emirates, had sent fighter jets and Apache attack helicopters to cover Yemeni troops fighting rebels on the ground, a pro-government military source told AFP.
In a lengthy televised speech from an undisclosed location, the country's rebel chief appeared to admit the alliance had made headway into Hodeida.
International aid groups have appealed to both the rebels and the alliance to allow civilians to escape the densely-populated city of 600,000 people.
The International Committee of the Red Cross appealed for the warring parties to "spare civilians and civilian infrastructure" including ambulances, hospitals, electricity and water plants.
The first youngster was confirmed killed in the fighting Wednesday, with Save the Children telling AFP a 15-year-old had died of shrapnel wounds at a hospital in Hodeida.
Millions of people across Yemen are dependent on humanitarian aid to survive a deadly trifecta of war, disease and looming mass starvation - and nearly 80 percent of that aid comes through Hodeida.
The Houthis, northern tribesmen linked to Iran, seized large parts of Yemen in a 2014 takeover, including the capital Sanaa.
Saudi Arabia and its allies joined the Yemeni government's war against the Houthis the following year, driving the rebels back but failing to retake Sanaa and Hodeida.
Nearly 200 combatants have been killed over the past week in the fight for Hodeida on both sides.
Rebel chief Abdulmalik al-Houthi on Wednesday acknowledged he was outnumbered, but appeared undaunted even while appearing to admit to incursions by the Saudi-led coalition.
"The enemy benefits from its numbers, which it has increased even further to pressure the city of Hodeida," al-Houthi said.
"Does the enemy think that penetrating this or that area, or seizing this or that area, means we will be convinced that we should surrender and hand over control?
"This is not happening and will not happen ever."
A medical source told AFP on Wednesday that the Houthis had forced medical staff out of the 22 May Hospital - one of Hodeida's main medical facilities - and stationed snipers on top of the building.
Saudi Arabia and its allies accuse Iran of using the port to smuggle missiles to the Houthis, a charge Tehran denies.
International aid groups rely on Hodeida to ship into Yemen aid - including basic vaccines and water sterilisation tablets - and on Wednesday they called for the urgent evacuation of residents.
One of the city's biggest hospitals, Al-Thawra, is now only "metres away from an active frontline", said International Committee of the Red Cross spokeswoman Mirella Hodeib, speaking from the Yemeni capital.
Juliette Touma, spokeswoman for the UN children's fund (UNICEF), said: "We're talking about dying children who are currently at the hospital.
"What we are fearful about is that the escalation of violence is highly likely to jeopardise humanitarian efforts that are life-saving," she told AFP, warning the already dire situation would likely worsen.
The war and the collapse in the Yemeni rial has left most of the population dependent on humanitarian aid -- with nearly 14 million at risk of famine.
Hassan Basha, a security advisor with Save the Children in Sanaa, said his group was treating five children for wounds sustained from the fighting. A sixth, the 15-year-old boy, had died, Basha said.
Doctors Without Borders (MSF) on Wednesday announced it had suspended its work in the Daleh region, east of Hodeida province.
"There have been multiple security incidents directly targeting patients, staff and MSF-supported medical facilities in the area. We are left with no choice, but to close all activities in Daleh governorate," said Ton Berg, the group's head of mission in Yemen.
At least 10,000 Yemenis have been killed since 2015, according to the World Health Organisation, and the country now stands on the brink of famine.