Ajax have signed young Iceland striker Kolbeinn Sigthorsson from AZ for an undisclosed fee.

The 21-year-old has signed a four-year contract at the Amsterdam ArenA, having impressed by scoring 18 goals in 43 appearances last season - his first as a professional.

It is reported Ajax paid around €4m to AZ.

"I'm proud to have signed a contract with Ajax," Sigthorsson, who will wear the No9 jersey for the Eredivisie champions, told the club's official website.

"That's a great number for me. Many great players have worn that number.

"I'm hoping to become a better player here. I hope I can do great things for the club, win titles, and I want to score more goals than last year."