Reigning Tour de France champion Jonas Vingegaard (Visma-Lease a Bike) has suffered a broken collarbone, "several" broken ribs and a collapsed lung in a crash at Itzulia Basque Country, his team has revealed.
Meanwhile, Remco Evenepoel (Soudal Quick-Step) broke his collarbone and shoulder blade in the same crash.
Vingegaard fell hard on a corner with under 40km to go on Thursday's fourth stage, and lay at the roadside motionless. He was then put on a stretcher and taken by ambulance to hospital.
In a statement, Vingegaard's team said he is "stable and conscious".
"Examinations at the hospital have revealed that he has a broken collarbone and several broken ribs. He remains in hospital as a precaution. Thank you for all your messages," the statement continued.
The team issued an update on Friday, adding: "Further examination in the hospital revealed that he also suffered a pulmonary contusion and pneumothorax." The latter is more commonly known as a collapsed lung.
It is uncertain at this stage how long Vingegaard will be sidelined for. He was next due to race in early June at the Critérium du Dauphiné, where he planned to defend his title, before lining up to do the same at the Tour de France.
Primož Roglič (Bora-Hansgrohe) and Evenepoel were also involved in the crash at Itzulia Basque Country, in which riders appeared to slide into a concrete drainage ditch.
The pair both abandoned the race, like Vingegaard, but were shown to be conscious and talking. Evenepoel was able to walk away, having bunnyhopped over the ditch and crashed on grass.
"Remco will travel to Belgium on Friday, where he will undergo an operation on his collarbone, and further examination, at the hospital in Herentals," a spokesperson for Soudal Quick-Step said.
Roglič did not suffer any fractures, his team later confirmed. The Slovenian left the race in a team car, dealing a thumbs up to the TV cameras.
With a fleet of ambulances needed to tend to the injuries, the race organisers took the decision to neutralise the stage. The win was contested by the six riders in the breakaway, with Intermarché-Wanty's Louis Meintjes crossing the line first.
"It's a victory that does not feel like it," Meintjes said afterwards. "You want the race to be fair for everyone. I send my thoughts to all injured riders."
Also involved in the crash were Jay Vine (UAE Team Emirates), Sean Quinn, Alexander Cepeda (EF Education-EasyPost), Steff Cras (TotalEnergies) and Natnael Tesfazion (Lidl-Trek).
"Vine is conscious and talking," UAE Team Emirates confirmed, but added he "sustained a cervical and two thoracic spine vertebral body fractures."
Quinn was diagnosed with a concussion and a sternum fracture, EF Education-EasyPost said. While TotalEnergies confirmed Cras suffered pneumothorax, "several" fractured ribs and a two fractured vertebrae.
Tesfazion's Lidl-Trek revealed the Eritrean had "numerous contusions and abrasions", but no fractures. "Further treatment is currently underway, particularly on the right elbow, the most severe injury sustained by the rider," his team said.
The Spanish race had already seen a handful of major withdrawals, with Tom Pidcock (Ineos Grenadiers) and David Gaudu (Groupama-FDJ) among those abandoning earlier in the week.
