“I am extremely concerned about military escalation in #Hodeida & their humanitarian & political impact,” the UN special envoy to Yemen, Martin Griffiths, said in a tweet on Wednesday after government forces launched an offensive on the key port.
The UN envoy also issued a statement, saying he was continuing to hold negotiations on keeping Hudaydah open to aid deliveries.
"We are in constant contact with all the parties involved to negotiate arrangements for Hudaydah that would address political, humanitarian, security concerns of all concerned parties," said Griffiths in the statement.
He called on all sides to "exercise restraint and to give peace a chance."
Forces backed by the Saudi-led coalition on Wednesday launched an offensive against Hudaydah, aiming to take the city that has been controlled by the ruling Houthi movement, Presstv reported.
The Saudi-led coalition claims that the Houthi Ansarullah movement is using Hudaydah for weapons delivery, an allegation rejected by the fighters.
Coalition sources said the alliance carried out 18 airstrikes on Houthi positions on the outskirts of Hudaydah.
Meanwhile, the Houthis deployed military vehicles and troops in the city center and near the port, as warplanes struck the coast to the south, residents on condition of anonymity told Reuters.
Yemen's War Media outlet also said that the army and fighters from Popular Committees inflicted heavy damage on aggressors in Hays district, destroying 10 personnel carriers and armored vehicles.
The Yemeni forces also repelled two attacks on al-Durayhimi and al-Fazah districts, killing and injuring dozens of aggressors.
'Hundreds of children at risk in Yemen battle'
The attack comes as aid groups warned on Wednesday that some 300,000 children risk death, injury and starvation as they are trapped in Hudaydah, which is the main route for food to reach most Yemenis, 8.4 million of whom are already on the verge of famine.
Jolien Veldwijk, acting country director for the charity CARE International, called the attack "catastrophic, hopeless and devastating," worsening hunger as food will become harder to find and more expensive.
"Kids are most vulnerable so they will die first ... Parents will have to make a decision of either feeding their children or treating them,” Veldwijk added.
"With this assault, (children) are now suffering more hunger and death," Anas Shahari, a spokesman for Save the Children, told Reuters by phone from the Yemeni capital Sana’a. Shahari said he feared that the condition of some 300,000 children would worsen with less access to food, water and medicine.
"I could see children who are hungry, children who are on the streets with their ribs sticking out, babies unable to cry because they are so malnourished," he said. "That was the situation before, and now it is going to get worse."
The UN has warned that the battle in Hudaydah, which has a population of 600,000, could cost up to 250,000 lives, as well as cutting off aid and other supplies to millions of people.