Ajax midfielder Abdelhak Nouri has suffered "serious and permanent brain damage" after collapsing during a pre-season friendly on Saturday, the Eredivisie club have announced.

The 20-year-old Dutchman required emergency ambulance treatment on the field during a meeting with Werder Bremen in Zillertal, Austria and he was subsequently airlifted to hospital.

Ajax, who earlier in the week revealed Nouri had experienced heart arrhythmia, tweeted on Thursday that he had been "diagnosed with serious and permanent brain damage."

Nouri - known as 'Appie' - made 15 appearances for Ajax's first team last season, including three in the Europa League, and scored on his senior debut in a 5-0 win over Willem II in the KNVB-Beker.

On Monday Ajax revealed Nouri's heart was functioning normally and appeared to be undamaged, adding that it was "too soon to say anything about his recovery, as his brain function cannot be tested properly as long as he is kept asleep."

It was then confirmed that he would be released from an artificial coma.

The capital club's opponents on Saturday, Bundesliga side Bremen, were among the first to convey their support, tweeting: "Our prayers are with him #StayStrongAppie".