SEOUL — At least seven people were killed and dozens of others injured after an explosion started a fire on Thursday at the offices of a law firm in the southern city of Daegu, South Korea, according to the police.

The police said the blaze was being investigated as arson, and after a review of security camera footage, a 50-year-old man was identified as a suspect. The man is believed to have died at the site, the police said. He was not immediately identified.

No information about a potential motive was immediately released, but local news outlets reported that the police were investigating whether the fire had been started by a disgruntled client over a case.

The fire broke out at about 10:55 a.m. in a seven-story office building next to Daegu District Court, according to an officer with the police department in Daegu, which is about 170 miles from Seoul, the capital. The authorities said they received reports of a loud explosion and black smoke coming from the law firm’s offices, Yonhap News Agency reported.

Nearly 60 fire trucks and about 150 firefighters were deployed to the site, and they extinguished the fire in about 20 minutes. Firefighters rescued about 40 people from the building, officials said.

South Korea has seen a number of high-profile fires in recent years, some of which have been linked to lax safety standards. In April 2020, a fire at a warehouse in Icheon, southeast of Seoul, killed 38 workers. Another fire engulfed a high-rise apartment building in the city of Ulsan in October of that year, forcing the evacuation of hundreds of people. In 2018, a blaze at a hospital that also served as a nursing home in the southern city of Miryang killed 37.

In 1995, gas leaks at Daegu construction sites set off explosions and flames that killed at least 100 people, many of them teenagers.

Jin Yu Young reported from Seoul, and Tiffany May from Hong Kong. John Yoon contributed reporting from Seoul.