At least 22 people were killed in a Houthi rebel missile strike on a mosque south of the strategic Yemeni city of Marib, officials said on Monday.

“Twenty-two people, including children, were killed and 19 others were injured in a Houthi missile attack on a mosque… in Al-Jawba district” on Sunday night, a pro-government military official told AFP. The official, who spoke on condition of anonymity, said the mosque also had a religious school.

Yemen’s Information Minister Moammar al-Eryani said on Twitter that 29 people, including women and children, were killed in the attack.

“This horrific massacre is within a series of systematic killings of civilians by the terrorist Houthi militia,” he wrote in English.

The Houthis have yet to comment on the attack, which comes as fighting between the Iran-backed rebels and government forces supported by a Saudi-led military coalition intensifies.

On Thursday children were among 13 people killed when a missile fired by the rebels struck a tribal leader’s home in Al-Jawba, according to military and medical officials.

Marib, capital of the oil-rich province of the same name, is the internationally recognized government’s last bastion in northern Yemen.

The Houthis began a major push to seize the city in February and, after a lull, they have renewed their offensive in recent weeks. They claimed this week to have reached the vicinity of Marib city and to have nearly surrounded it.

The Saudi-led coalition has been conducting an aerial bombing campaign since October 11 to prevent the rebels from reaching Marib city.

Since then, more than 2,200 Houthi fighters have been killed in Al-Jawba and two other districts, according to the coalition. The rebels rarely comment on losses, and AFP could not independently verify the toll.

Yemen’s civil war began in 2014 when the Houthis seized Sanaa, prompting Saudi-led forces to intervene to prop up the government the following year.

Tens of thousands of people have died and millions have been displaced in what the United Nations calls the world’s worst humanitarian crisis.