The explosion occurred Saturday at the Zaher district in the province of Bayda, the Houthi rebel-run Health Ministry said in a statement. At least 67 others were injured, including 40 in critical condition.

The ministry said rescue teams were searching for those reported missing. It wasn’t immediately clear what caused the explosion.

Footage circulated online showing a massive fire that sent columns of smoke into the sky and left vehicles charred and burning.

Bayda is controlled by Iranian-backed Houthi rebels, who have been at war with Yemen’s internationally recognised government for more than a decade.

Elsewhere in Bayda, the Houthis attacked and looted Hanaka al-Masoud village in the al-Qurayshiya district last week, according to the internationally recognised government. It said there were fatalities but gave no figures.

Information Minister Moammar al-Eryani said the attack came after a weeklong siege of the village.

“This horrific attack targeted citizens’ homes and mosques, and resulted in many casualties, including women and children, and the destruction of property,” he said.

Rights activist Riyadh al-Dubai said the Houthis detained dozens of men and looted homes, seizing valuables such as gold, money, daggers and other possessions. He said shelling by the Houthis had continued relentlessly day and night for more than five days.

The US Embassy in Yemen condemned the attack, saying in a statement that the “deaths, injuries, and wrongful detentions of innocent Yemenis perpetrated by Houthi terrorists are depriving the Yemeni people of peace and a brighter future.”

Yemen’s civil war began in 2014, when the rebels took control of the capital, Sanaa, and much of the country’s north, forcing the government to flee to the south, then to Saudi Arabia. A Saudi-led coalition entered the war in March 2015, backed at the time by the US, in an effort to restore the internationally recognised government.

The war has killed more than 150,000 people including civilians and combatants, and in recent years deteriorated largely into a stalemate and caused one of the world’s worst humanitarian crises.