Meanwhile, dozens of Yemeni rebels have been killed in battles and air strikes in Hodeida, medics said Sunday, as pro-government forces advanced in the insurgent-held Red Sea port city.
The foreign secretary, Jeremy Hunt, criticised both the Saudi-led coalition and opposition Houthi rebels backed by Iran on Monday, saying: "For too long in the Yemen conflict, both sides have believed a military solution is possible, with catastrophic consequences for the people".
Geert Cappelaere told The Associated Press in an interview from Yemen that recent USA calls for a cease-fire are imperative to ending the almost four-year war, which pits a Saudi-led coalition against Iran-aligned rebels known as Houthis.
Residents confirmed to Xinhua that the two-warring sides started exchanging artillery shelling and large explosions were heard across the city.
The alliance, which relies on Western arms and intelligence, faces a challenge to seize the heavily-defended city without causing heavy casualties at time of increasing global scrutiny over the war that has killed more than 10,000 people.
Thirteen pro-government troops were killed, medical sources in Aden and Mokha - where the fighters were transported.
"Unfortunately, Amal is not the only Yemeni child suffering that fate", he told a news conference in Amman, Jordan.
Yemen's internationally recognised government On Thursday welcomed a call from the USA for peace in the conflict-torn country, state-run news agency Saba said.More news: Rafael Nadal an injury doubt for London — ATP Finals
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Hodeida port is the entry point for more than 70 percent of imports into the impoverished country, which is teetering on the edge of starvation.
Angelina Jolie, the USA actress and a special envoy for the United Nations refugee agency, said the global community had been "shamefully slow" to act on Yemen.
"As an global community we have been shamefully slow to act to end the crisis in Yemen", she said in a statement Sunday.
The United Nations has listed Yemen as the country with the world's biggest humanitarian crisis, with 7 million Yemenis on the brink of starvation and cholera causing more than 2,000 deaths.
UN Secretary-General Antonio Guterres on Friday called for a halt to violence in Yemen to pull the country back from a "precipice" and build momentum toward talks on ending the war.
After UN-backed peace talks collapsed in September, the coalition announced it was re-launching an assault on Hodeida.
The Yemeni government is seeking to expel Houthi rebels out of the strategic city of Hodeidah in recent days despite warnings by worldwide humanitarian agencies.
Saudi Arabia and its allies intervened in the war in 2015 to bolster Yemeni president Abedrabbo Mansour Hadi after the rebels took over the capital Sanaa.