United Nations Secretary-General Antonio Guterres expressed deep concern on Monday over a significant escalation in Yemen’s conflict, his spokesman said, amid a counteroffensive aimed at reclaiming territory from Ansar Allah forces.

“The Secretary-General is deeply concerned by the sharp escalation in fighting, which has intensified markedly in recent days,” said Stephane Dujarric, the spokesperson for Guterres. He also condemned Ansar Allah’s continued cross-border attacks against Saudi Arabia.

Meanwhile, Yemen’s internationally recognized government launched an ambitious military operation targeting Ansar Allah positions, including strikes in the capital city of Sanaa, which has been under the group’s control for more than a decade. According to the Yemeni military, over 1,000 air and ground strikes were carried out as part of the offensive that aims to regain full control over territory held by Ansar Allah.

Supporting the Yemeni government, a coalition led by Saudi Arabia reported executing approximately 100 air sorties at dawn on Monday. The government reiterated its goal, announced on Sunday, to retake all areas under Ansar Allah control, which includes much of Yemen’s population centers.

The intensification of fighting follows a series of recent Ansar Allah advances, particularly last month when the group captured large sections of coastline along the Red Sea and the strategically critical Bab Al Mandab Strait—a key maritime passage for global oil and cargo shipments.

Ansar Allah has also maintained cross-border attacks into Saudi Arabia since the civil war in Yemen escalated again. They declared a maritime blockade affecting Saudi shipping, adding to regional tensions.

A source within Saudi Arabia’s energy sector confirmed that an attack on Sunday disrupted operations on the East-West pipeline, halting crude oil flow to the Red Sea. This pipeline serves as a vital export route for Saudi Arabia, especially following Iran’s blockade of the Strait of Hormuz, which had been a principal maritime corridor in the wider Middle East conflict.

The recent surge in hostilities underscores the continuing instability in Yemen, where over a decade of conflict has resulted in widespread humanitarian crises and disruptions to global trade routes. The UN Secretary-General’s remarks highlight growing international concern over the renewed violence and its potential to further destabilize the region.