A strong earthquake in southern China’s Yunnan province toppled thousands of homes Sunday, killing at least 367 people and injuring more than 1,800.

About 12,000 homes collapsed in Ludian, a densely populated county about 277 miles northeast of Yunnan’s capital, Kunming, China’s official Xinhua News Agency reported.

The magnitude-6.1 quake struck at 4:30 p.m. at a depth of 6 miles, according to the U.S. Geological Survey. Its epicenter was in Longtoushan township, 14 miles southwest of Zhaotong, the Ludian county seat.

Ma Liya, a resident of Zhaotong, told Xinhua that the streets there were like a “battlefield after bombardment.” She added that her neighbor’s house, a new two-story building, had toppled, and said the quake was far worse than one that struck the area in 2012 and killed 81 people.

“The aftermath is much, much worse than what happened after the quake two years ago,” Ma said. “I have never felt such strong tremors before. What I can see are all ruins.”

Most of the deaths — 357 — were in Zhaotong City, Xinhua said. Ten other people died in Quijing City.

News reports said rescuers were still trying to reach victims in more remote towns Sunday night.

Photos on Weibo, China’s Twitter-like social media site, showed rescuers searching through flattened buildings and people injured amid toppled bricks.

U.N. Secretary-General Ban Ki-moon offered “his condolences to the Chinese Government and the families of those killed,” according to a statement from his office. The statement said the U.N. is ready to “lend its assistance to efforts to respond to humanitarian needs” and “to mobilize any international support needed.”

The White House also offered its condolences.

“Our thoughts and prayers are with the families of those that lost their lives,” National Security Council deputy spokeswoman Bernadette Meehan said. “The United States stands ready to assist.”

Many of the homes that collapsed in Ludian, which has a population of about 429,000, were old and made of brick, Xinhua said, adding that electricity and telecommunications were cut off in the county.

The mountainous region where the quake occurred is largely agricultural, with farming and mining the top industries, and is prone to earthquakes.

Relief efforts were underway, with more than 2,500 troops dispatched to the disaster region, Xinhua said. The Red Cross Society of China allocated quilts, jackets and tents for those made homeless by the quake, while Red Cross branches in Hong Kong, Macau and neighboring Sichuan province also sent relief supplies.