Updated

Airstrikes blamed on a Saudi-led coalition fighting Shiite rebels in Yemen hit a busy market and a bus on Thursday in the country's north, killing at least 20 people, including children, Yemeni tribal leaders said on Thursday.

As many as 35 were also wounded in the attack, which took place in the Dahyan district in Saada province, a stronghold of the rebels known as Houthis, the elders said. The province lies along the border with Saudi Arabia.

The airstrikes hit pedestrians in the area of the attack and also struck a bus that was ferrying civilians, including many school children, the elders said, speaking on condition of anonymity for fear of reprisals.

There was no immediate comment from the coalition, which is led by Saudi Arabia and which is fighting to restore Yemen's internationally recognized government to power. The Saudi coalition has been at war with the Houthis since March 2015. The rebels control much of northern Yemen, including the capital, Sanaa.

The International Committee of the Red Cross said on Twitter that an ICRC supported hospital received dozens of dead and wounded following the attack that hit a bus with children.

"Scores killed, even more injured, most under the age of ten," the head of the ICRC in Yemen, Johannes Bruwer, said on his Twitter account, adding that the ICRC in Yemen is "sending additional supplies to hospitals to cope with the influx."

The rebel-run Al Masirah TV gave a different casualty toll, saying the attack killed 39 people and wounded 51, mainly children. Disparate casualty tolls are common in the immediate aftermath of large attacks.

Later on Thursday, sounds of blasts from airstrikes that hit the capital, Sanaa, reverberated across its southern and western neighborhoods. It was not immediately clear if there were any casualties in those strikes.

Yemen's stalemated, three-year war has killed over 10,000 people, badly damaged Yemen's infrastructure and crippled its health system. The coalition faces widespread international criticism for its airstrikes in Yemen that kill civilians.

Impoverished Yemen, on the southern tip of the Arabian Peninsula, is now in the world's worst humanitarian crisis, with more than 22.2 million people in need of assistance.

Last week, Yemeni medical officials said the coalition conducted airstrikes in the rebel-held port city of Hodeida, killing at least 28 people and wounding 70. But the coalition denied carrying out any attacks in the city, saying it follows a "strict and transparent approach based on the rules international law."

The fight for the port of Hodeida, a key lifeline for supplies and aid for Yemen's population on the brink of starvation, has become the latest battleground in the devastating war.

The Iran-aligned Houthis regularly fire into Saudi Arabia and have targeted its capital, Riyadh, with ballistic missiles. They say their missile attacks on the kingdom are in retaliation for air raids on Yemen by the Western-backed coalition.

On Wednesday, the official Saudi Press Agency carried a statement by the Saudi-led coalition saying fragments of a missile fired by the Houthis into the kingdom's south killed one civilian and wounded 11.

The coalition said the projectile, fired toward the southwestern Saudi city of Jizan, was intercepted and destroyed. It also said the missile was launched "deliberately to target residential and populated areas."

The U.N. special envoy for Yemen, Martin Griffiths, has been pushing to bring the warring parties to restart peace talks. He recently announced plans to invite Yemen's warring parties to Geneva on Sept. 6 to hold the first round of consultations.