Zayn Malik Cancels U.S. Tour After Mysterious Hospitalization

Zayn Malik is shifting his schedule in a big way after his recent hospitalization ... he's canceled his U.S. tour.

The One Direction alum took to Instagram to share that he's seriously scaled back the "Konnakol Tour" -- going from 32 shows to just 9.

He didn't specify why, exactly ... just noted that he had to take a look at his schedule and cut a bunch of concerts.

According to his website, Zayn's axed all of his U.S. dates, as well as some shows across the pond ... pulling the plug on his dates in Dublin, Glasgow, and Birmingham.

The tour -- his first headlining arenas as a solo artist -- was supposed to start May 12 in Manchester ... but that show's been pushed to May 24.

The run will now kick off May 23 in London. He's still set to play 3 stops in Mexico in June, and will hit Chile, Argentina, Brazil, and Peru in October ... all as originally scheduled.

This comes just two weeks after Zayn revealed he'd been in the hospital ... but didn't explain why or how he ended up there.

All he said was he was he'd had "a long week" and was "unexpectedly recovering" ... mentioning doctors, nurses, and a cardiologist.

At the time, our sources told us the singer was dealing with ongoing health issues and seeking treatment from a professional described as the number one cardiologist in the world.

Zayn's still keeping the details of his mysterious hospitalization under wraps ... only sharing in this new post that he's home from the hospital and recovering, saying he's "doing well" and plans to bounce back "better and stronger" than he was before.