Two military horses that bolted and ran miles through the streets of London after being spooked by construction noise and tossing their riders were in serious condition Thursday after undergoing operations, a U.K. government official said.

The animals were among a group of four horses that broke free during routine exercises Wednesday near Buckingham Palace and caused chaos as they galloped loose through central London during morning rush hour. A fifth horse tried to bolt but couldn’t break free.

“Three of them are fine, two of them are unfortunately in a relatively serious condition and obviously we will be monitoring that condition,” defense minister James Cartlidge told Sky News. “They are in a serious condition, but as I understand, still alive.”

Three soldiers thrown from their steeds were hospitalized with injuries, but were expected to fully recover and return to work.The British Army said three of the horses were expected to return to duty, but the fate of the two with the worst injuries was unclear.

Neither was believed to have broken bones, but a horse named Quaker was transferred to an equine hospital for specialist care, an army spokesperson said.