At least 58 Yemeni government troops have been killed in Houthi missile and drone attacks, a military source said. The attack marks one of the deadliest days in the country's civil war in four years.
Violence also spilled into neighbouring Saudi Arabia.
The attacks on Thursday targeted military positions in the provinces of Marib and Hadramout, with dozens more troops wounded, according to the source, who spoke on condition of anonymity.
A military official described the strikes as the deadliest on government forces since 2022.
Houthi military spokesperson Yahya Saree said the attacks targeted government positions in response to what he described as a Saudi-backed military buildup.
Yemen's Defence Ministry said the armed forces would respond "at the appropriate place and time."
Attacks spill into Saudi Arabia
The escalation crossed the border on Thursday, with Houthi attacks wounding 11 civilians in Saudi Arabia's southern Najran region, according to the Saudi-led coalition.
Coalition spokesperson Major General Turki al-Malki said the wounded included seven Saudis, two Egyptians, one Yemeni and one Pakistani national.
He accused the Houthis of carrying out indiscriminate attacks on civilian areas and said coalition forces would continue taking measures to protect civilians.
Regional tensions deepen
The attacks come as Yemen is increasingly drawn into the US-Israeli war with Iran, with the Iran-backed Houthis stepping up attacks on both government forces and neighbouring Saudi Arabia.
The Houthis have intensified attacks since last month after announcing a maritime blockade on Saudi ports and launching strikes on Saudi shipping and military targets.
Saudi Arabia has led a military coalition backing Yemen's internationally recognised government against the Houthis since 2015.
Although fighting had largely subsided following a UN-brokered truce in 2022, recent hostilities have reignited one of the Middle East's longest-running conflicts.
