Four people are thought to be trapped beneath a multi-story building after it collapsed in the Kenyan capital city of Nairobi.

On Friday, Jan. 2, the Kenya Red Cross said, “a building being constructed collapsed in the Shopping Centre area in South C of Nairobi County early on Friday morning.”

“A multi-agency response team is at the scene controlling the situation,” the Kenya Red Cross said on X.

Just a few hours later, the organization said that the area had been cordoned off as the National Disaster Management Unit, Nairobi City County, the National Police Service, and the Kenya Red Cross continued search and rescue operations.

Soon after, the Kenya Red Cross reported more on the situation, adding that search and rescue efforts were continuing into the night, as a building next to the scene was being inspected, which showed signs of the possibility of collapse.

Four people were believed to be trapped in the collapse, Geoffrey Ruku, the Cabinet secretary in charge of public service, told reporters, according to the Associated Press.

Safia Ali Aden, described as the sister of one of the trapped, told reporters on the scene her brother made a phone call “while under there.”

“We are asking the government to be speedy in the rescue so we can find my brother alive,” she said, per the news organization.

The reason for the collapse is not known yet.