AL-MUKALLA, Yemen: Five Houthi ballistic missile engineers, including foreigners, were killed in a large explosion that rocked Houthi-held Sanaa, Yemen’s Information Minister Muammar Al-Eryani said on Sunday.

He slammed the Houthis for endangering the lives of thousands of people who live in the capital by storing and manufacturing weapons inside residential areas.

The Yemeni minister said the five engineers were assembling a ballistic missile at a military location on Saturday near Sanaa airport, which was being used as a missile factory and rigging drones with explosives.

“This incident confirms the continued flow of Iranian weapons to the Houthi militia, its indifference to international community, disavowal of its obligations, & exploitation of UN-sponsored truce to accumulate more Iranian smuggled weapons in residential areas, & using civilians as human shields,” Al-Eryani said on Twitter.

Less than a day after the Houthi engineers were killed, a group of Omani diplomats arrived in militia-occupied Sanaa to discuss extending the UN-brokered truce.

The Houthi movement’s chief negotiator, Mohammed Abdul Salam, said he and an Omani delegation touched down in Sanaa on Sunday on an Omani plane to discuss with the Houthi leaders issues related to the truce and the UN Yemen proposal on addressing humanitarian and economic problems.

The Omanis arrived in Sanaa to push the Houthis into accepting the UN Yemen envoy’s proposal in ending their siege on Taiz and extending the truce, which is due to expire on Aug. 2.

UN, Western and regional envoys are pushing the Yemeni factions into extending the truce to six months and turning it into a sustainable peace deal to end the war.

The visit came as the UN Yemen envoy, Hans Grundberg, failed to convince the Houthis to accept his proposal on opening roads in Taiz and alleviating their siege on the city.

The Houthi objection blocked progress in the implementation of the truce and threatened to ruin it as the internationally recognized government of Yemen refused to move to discuss other issues before the Houthis opened roads in Taiz.

The Yemeni government said the Houthis did not implement all of the truce’s terms, refused to pay the salaries of the public servants in areas under their control despite generating more than 100 billion riyals ($86,956,522) from oil ships during the truce and continued attacking government-controlled areas in Taiz and Hodeidah, Marib and other areas.

On Saturday, the UN Yemen envoy returned empty-handed from Aden after the president of the Presidential Leadership Council, Rashad Al-Alimi, snubbed a meeting with him in protest against the Houthi violations of the truce, their objection to opening roads in Taiz and the UN’s soft stand with the movement.