HARBIN -- Local authorities have set up a team to investigate a gymnasium collapse in northeast China's Heilongjiang province on Monday that left three junior high school students dead and another two injured.

A group of seven junior high school students started playing basketball at the Yuecheng gymnasium in Huanan county in the city of Jiamusi at about 6 pm on Monday, while the ceiling of the gymnasium collapsed at about 7:20 pm, according to the press office of the Huanan county government.

Three students escaped by themselves, with two suffering no injuries and one being sent to hospital for treatment. The four trapped students were rescued and rushed to hospital, but three died after emergency treatment failed, it said. Rescue efforts concluded at 0:35 am on Tuesday.

The two hospitalized students did not sustain life-threatening injuries, with one suffering a fibula fracture and minor facial abrasions, while the other suffered minor soft tissue abrasions.

The discipline inspection and supervision departments of Jiamusi and Huanan have formed a combined investigation team in a bid to determine the cause of the collapse.

The gymnasium was part of the No 7 building of the Yuecheng plaza complex. Construction of the building finished in July 2018 and it went through completion acceptance in July 2020, according to the press office.

The building has two sections. One is a two-story section 2,534 square meters in size, while the other is a 675-square-meter single-story section. The latter section suffered the collapse on Monday.

Since December 2022, the building has been run by a fitness club, which operates sports activities such as basketball, table tennis and badminton, it said.

Owners of the gymnasium building and fitness club have been put under police control.