LONDON (AP) — 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 UK 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,” defence 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 hospitalised 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.

Vida, a white horse seen drenched in blood as it galloped down Aldwych, in between London’s historic financial centre and the busy West End theatre district, was treated for lacerations.

“Vida was the most visibly injured and the pictures of the horse running through London soaked in blood were horrifying,” the army said in a statement.

The other loose horses from the Household Cavalry, the ceremonial guard of the monarch and a feature of state functions in London, are named Trojan and Tennyson.

During the wild spectacle captured by stunned commuters and shared on social media, the horses had near misses with cyclists and a rider on a motorbike at a traffic light.

Vida ran alongside Trojan, a black horse that could be seen sideswiping a taxi as it turned into oncoming traffic after running through a red light at an intersection.

One of the animals shattered the windows of a taxi it struck outside the Clermont Hotel and another smashed a windshield when it slammed into a tour bus.

Two of the horses were corralled at Limehouse about 5 miles (8 kilometres) from where they bolted. All the captured horses were taken back to barracks in Hyde Park.

Cartlidge said the army trains with about 150 horses every day, so the incident was exceptionally rare.

“Unfortunately we have seen what has happened, but all I can say is the crucial thing … no serious injuries to the public as far as we are aware, and of course we will be keeping an eye on the situation,” he told LBC.

The horses had been training for an upcoming military parade and were spooked by the crashing sound of construction materials at a work site in Belgravia, a swanky neighbourhood just to the west of the palace, said Matt Woodward, commanding officer of the Household Cavalry Mounted Regiment.

A day after the incident, more than 150 horses and close to 200 participants took part in the regiment’s annual inspection at Hyde Park to demonstrate readiness for summer pageantry including Trooping the Color and state visits.

A small crowd gathered as mounted riders, dressed in black, red and gold uniforms with golden helmets, trotted to the beat of a brass band.