Nicolo Zaniolo completed his transfer to Galatasaray from Roma on Wednesday, ending a weeks-long spat which finished with the Italy international completely frozen out at his former club.

Roma said in a statement that Zaniolo had joined the Istanbul giants "on a permanent basis".

Italian media report that Galatasaray offered Roma 16.5 million euros ($17.7 million) with add-ons of up to 13 million euros to take Zaniolo off their hands.

The 23-year-old, who has a 35 million euro release clause in his four-year contract, has moved to Turkey in order to not spend the rest of the season on the sidelines at Roma.

He was pushed aside, reportedly at the request of Roma's American owners, after putting in a transfer request, refusing to be selected for matches and then turning down a 30-million-euro move to Bournemouth.

Coach Jose Mourinho said that Zaniolo - who fled Rome after claiming he was threatened by fans outside his home - had told him and his teammates that he never wanted to play for Roma again.

On Wednesday Roma's general manager Tiago Pinto launched one last barb at Zaniolo during a press conference to mark the end of the club's transfer activities.

"Even I can decide that I'm worth 'X' amount of money," said Pinto.

"But if I leave Roma and the only clubs that come in for me are Bournemouth and Galatasaray, then either I'm rubbish or something's not right."

It is an ignominious end at Roma for Zaniolo, who was considered one of Italy's brightest young talents when he burst onto the scene with the capital club as a teenager.

His early career was severely harmed by serious injuries to both knees, but he fought back last season and under Mourinho was key to Roma's Europa Conference League triumph, scoring the winning goal in the final against Feyenoord to secure their first ever major European trophy.