The Iran-backed Houthi militia in Yemen have launched coordinated attacks on the besieged city of Taiz, threatening to undermine a fragile UN-brokered truce.

The Houthis bombarded government troops with artillery fire, heavy weapons and explosive drones on the northwestern, northeastern and northern sides of the city before launching three simultaneous ground attacks in a bid to seize control of new areas. “The Houthi attacks sparked heavy clashes with the national army troops that ended early on Tuesday,” Col. Abdul Basit Al-Baher told Arab News.

Under the terms of the truce, the Houthis and the Yemeni government committed to joint work on opening roads in Taiz and other provinces. However, the Houthis continue to resist local and international calls to end their siege of Taiz as part of the truce, which came into effect at the beginning of April.

Al-Baher said the militia had recently deployed at least 200 new fighters, tanks and artillery pieces in Taiz, apparently preparing to launch more attacks to capture the city center from government forces.

“The truce is only from our side,” he said. “The Houthis have not respected it and are preparing for a long and fiercer battle in Taiz.”

Two rounds of talks between the Yemeni government and the Houthis in Amman on opening roads in Taiz collapsed as the Houthis insisted on opening only small and unpaved roads. To end the impasse, UN envoy Hans Grundberg proposed opening a main road and four small roads during the current round of talks. The Yemeni government accepted the proposal but the Houthis delegation asked for time to discuss it with their leaders.

Lana Nusseibeh, UAE permanent representative to the UN, called on Grundberg to intensify efforts to open the main road in Taiz, not only secondary ones, in order to alleviate the suffering of millions living under siege.

Nusseibeh said that, despite the truce, the Houthis have continued to mobilize and recruit across the areas they control, indoctrinating children with extremist ideology in the process.

The UAE envoy also commended Saudi Arabia for contributing $10 million toward the salvage operation of the stricken tanker FSO Safer, which poses an environmental risk.

Linda Thomas-Greenfield, US ambassador to the United Nations, said that now is the best opportunity for peace in Yemen, and the positive results of the truce are a “cause for genuine optimism.”

She said President Joe Biden’s visit to the region next month will seek to build on the progress already made.

Thomas-Greenfield, however, condemned the Houthi detention of a dozen UN and US staff and called for their immediate release.