NEW YORK: The UN chief on Thursday denounced the “escalation” in hostilities between Yemen’s Houthi militias and Israel, terming strikes on the Sanaa airport “especially alarming.”

“The Secretary-General condemns the escalation between Yemen and Israel. Israeli airstrikes today on Sana’a International Airport, the Red Sea ports and power stations in Yemen are especially alarming,” said a spokesperson for UN Secretary-General Antonio Guterres in a statement.

Israeli air strikes pummeled Sanaa’s international airport and other targets in Yemen on Thursday, with Houthi militia media reporting six deaths.

The attack came a day after the Houthis fired a missile and two drones at Israel.

World Health Organization chief Tedros Adhanom Ghebreyesus said on social media he was at the airport during the strike, with the UN saying that a member of its air crew was injured.

The United Nations put the death toll from the airport strikes at three, with “dozens more injured.”

UN chief Guterres expressed particular alarm at the threat that bombing transportation infrastructure posed to humanitarian aid operations in Yemen, where 80 percent of the population is dependent on aid.

“The Secretary-General remains deeply concerned about the risk of further escalation in the region and reiterates his call for all parties concerned to cease all military actions and exercise utmost restraint,” he said.

“He also warns that airstrikes on Red Sea ports and Sana’a airport pose grave risks to humanitarian operations at a time when millions of people are in need of life-saving assistance.”

The UN chief condemned the Houthi militias for “a year of escalatory actions... in the Red Sea and the region that threaten civilians, regional stability and freedom of maritime navigation.”

The Houthis are part of Iran’s “axis of resistance” alliance against Israel.