The strike coincides with the advance of coalition-backed Yemeni forces on the rebel-held Red Sea port of Hodeida, the main conduit for humanitarian supplies into a country teetering on the brink of starvation.
With the failure of diplomatic efforts, the clock is now ticking to the launch of a military offensive to liberate the port city. The UN has already dubbed Yemen the world's worst humanitarian disaster.
"But we are also anxious about the humanitarian situation".
U.N. shuttle diplomacy aims to avert assault on vital Yemen port
He accused the Houthis of seeking to destabilize Saudi Arabia and threaten regional and global security, stating that firing ballistic missiles at residential areas was a violation of worldwide Humanitarian Law.
His efforts to convince the rebels to hand over control of Al Hodeidah to UN-supervised global forces had failed, according to reports.
Eleven humanitarian aid agencies, including Oxfam and Save the Children, separately wrote to British Foreign Secretary Boris Johnson urging him to warn the coalition that it will lose British support if it attacks Hodeidah. Oosterom described Hodeidah as a "lifeline" for aid deliveries in Yemen. Malnutrition, cholera and other diseases have killed or sickened thousands of civilians over the years.
Médecins Sans Frontières (Doctors Without Borders) said on Monday that its cholera treatment center in the northwestern coastal town of Abs was hit by an airstrike from "by the Saudi and Emirati-led coalition", showing "complete disrespect for medical facilities and patients".
MSF said it had completely frozen its operations in Abs in response to the attack.
Almost 10,000 people have been killed since the alliance launched its intervention in Yemen in March 2015, contributing to what the United Nations has called the world's worst humanitarian crisis.
The Iran-backed rebels have maintained control of the city since 2015, and have not only used its port to smuggle weapons into Yemen but also to profit from illegally sold humanitarian aid. The U.N.is also pushing the militants to turn over arms in exchange for an end to the bombing campaign and a transitional governance deal.
"We are, at the present moment, in intense consultation", Guterres told reporters on Monday.
Guterres, the United Nations chief, said there has been a recent "lull in the fighting" to allow for discussions and hopefully avoid a battle.