A building collapsed during a planned demolition in Nairobi on Monday, resulting in at least four deaths and four injuries, Kenya’s Interior Ministry said. Officials said rescue workers from the army and other institutions were working at the scene to look for anyone still trapped under the rubble as injured people were taken away on stretchers.

The Interior Ministry said it was not immediately clear what went wrong during the demolition that led to the casualties. Images from the area showed victims being carried away after the collapse, while responders continued searching for possible survivors beneath the damaged structure.

The ministry said the building had been one of several earmarked for removal under the ongoing Nairobi River Regeneration Project. It did not provide additional details in its statement about the specific demolition steps or what caused the structure to fail.

At least two people were rescued, an Associated Press journalist at the scene in the Blue Estate community of Shauri Moyo reported, counting at least three bodies pulled from the collapsed structure. The Interior Ministry put the death toll at four, while the number of injured remained four, according to the ministry’s statement.

Kenya has faced recurrent building failures in Nairobi as housing demand has surged and, according to the Associated Press report, unscrupulous developers have sometimes bypassed regulations or violated building codes. After major collapses in the past, officials said the government ordered broader scrutiny of buildings to determine whether they met safety requirements.

The Associated Press report said that after eight buildings collapsed and killed 15 people in 2015, Kenya’s presidency ordered an audit of buildings across the country. The National Construction Authority found that 58% of the buildings in Nairobi were unfit for habitation, the report said, illustrating the scale of the safety challenge before Monday’s demolition collapse.