The NBA has fined JR Smith $50,000 (£30,387) for tampering with his opponents' shoelaces.

The New York Knicks shooting guard was warned by the league after he was spotted trying to untie Dallas Mavericks forward Shawn Marion's shoelaces during their game at the weekend.

However, the 28-year-old ignored the message, and tried the same trick against the Detroit Pistons' Greg Monroe on Tuesday.

The league handed Smith the fine for "recurring instances of unsportsmanlike conduct".

Smith has since taken to Twitter to apologise for his actions.