Doctors Without Borders said Friday that Saudi-led airstrikes on a residential district in Yemen’s southwestern city of Taiz had killed more than 65 civilians, including 17 people from one family.

If confirmed, it would be one of the largest tolls from airstrikes by Saudi Arabia and its military coalition partners since they began bombing Yemen five months ago in a campaign to crush the Houthi insurgency in the country.

Witnesses in Taiz said the airstrikes started at about 9:30 p.m. on Thursday and destroyed more than 17 buildings in the city’s Sala district. By the next morning, residents were still searching through the rubble with their bare hands to find survivors, Salah Dongu’du, the coordinator in Taiz for Doctors Without Borders, the medical charity, said in an interview.

Nasser al-Qadasi, a resident, said, “It was mass destruction.”

The airstrikes were part of a new outbreak of fighting over the past few days in Taiz, Yemen’s second-largest city and one of the country’s most heavily contested battlefields during the current conflict.