Championship side Middlesbrough have added to their squad before the close of the transfer window with the double signing of Kei Kamara and Jacob Butterfield.

Midfielder Butterfield, 23, joins from Norwich City on a three-year contract, with the option for a further 12 months, after failing to make a single league appearance for the Carrow Road outfit following his move from Barnsley in 2012.

Sierra Leone striker Kamara spent the second half of last season on loan with the Canaries, where he scored once in 11 matches, and has returned to England to play for Tony Mowbray's Boro.

The 29-year-old joins from Sporting Kansas City for an undisclosed fee.