The Yemeni government suspended its participation in peace talks to end the country’s civil war on Sunday after the Houthi movement and its armed allies seized a military base north of the capital Sanaa, two members of the official delegation to the talks said.

U.N. envoy Ismail Ould Cheikh Ahmed said in a statement that the Yemeni government stopped attending plenary sessions held in Kuwait because of developments in the governorate of Amran following the Houthi attack.

The statement says he has received assurances from the warring parties that they are committed to resolving difference without participating in joint sessions, and that the U.N. hopes to resume the talks.

The Houthi assault killed several of the soldiers defending the Umaliqa base. Unlike most of Yemen’s soldiers, those at Umaliqa had refused to take sides in the Yemeni civil war.

The Houthis had accepted this neutrality until they launched a surprise push into the facility in Amran province and seized its large reserve of weapons at dawn, local officials said.

“We have suspended the sessions indefinitely to protest these military actions and continued violations of the truce,” Reuters cited one member of the government delegation to the Yemen peace talks in Kuwait as saying.

The delegate declined to be named, citing rules on media commentary at the U.N.-sponsored peace talks.

Representatives from the Houthi movement and the allied party of former Yemeni president Ali Abdullah Saleh were not immediately available to comment.

Abdel-Malek al-Mekhlafi, Yemen’s foreign minister and the government’s top delegate to the negotiations in Kuwait, said in the immediate aftermath of the Houthi assault that it had “torpedoed” the talks.

“We will take the appropriate position in response to the Houthi crime at the Umaliqa base in Amran for the sake of our people and country,” he wrote on his official Twitter account, without elaborating.

The talks in Kuwait, which have been propped up by a truce largely holding since April 10, had been inching ahead in recent days and the Houthis said Saudi Arabia had released 40 Yemeni prisoners it had been holding on Saturday.

The war in the Arab impoverished country has killed at least 6,200 people and unleashed a humanitarian crisis in the most Yemeni areas. Yemen’s army has split and military bases and commanders have mostly either taken the Houthi or the government side.