Racist chants directed at Tottenham forward Son Heung-min during his side’s FA Cup quarter-final win over Millwall are to be investigated by the Football Association.

Taunts of “DVD” and “he’s selling three for a fiver” were directed at the South Korean during Spurs’ 6-0 victory.

The chants seem to refer to a racist stereotype of Asians as traders selling bootleg copies of films door to door.

Millwall boss Neil Harris said guilty fans should be dealt with “harshly”.

“It’s a shame to be talking about this,” added Harris after Son had scored a hat-trick to send Tottenham into the semi-finals.

“I didn’t hear anything but myself and the club won’t condone that if there is. I’m sure it will be investigated and left to the authorities.

“We want people dealt with harshly of course. It’s wrong in society and wrong in football.”

The Premier League club said any footage that could help catch those behind the alleged racism would be passed on.

A spokesperson said: “We strongly condemn the use of any racist language.”