Millwall manager Neil Harris has condemned racist chants directed from the club's fans at Tottenham striker Son Heung-min during Sunday's FA Cup quarter-final.

Son scored a hat-trick at White Hart Lane as Spurs thrashed the Lions 6-0, but their victory was marred by abusive songs aimed at the South Korean from the visiting supporters.

Millwall fans were heard chanting "DVD" and "You're selling three for a fiver" at Son during the first half, thought to be in reference to a stereotype of traders selling bootleg copies of films.

Son delivered the perfect response with his treble while further goals from Christian Eriksen, Dele Alli and Vincent Janssen secured an emphatic success for Mauricio Pochettino's team.

Harris admitted after the match he had not been aware of the chants but said they would be a blot on Millwall's excellent run in the competition.

"I didn't hear anything, but the club, we won't condone that," Harris said.

"We came here in the right spirit, to enjoy an FA Cup quarter-final, so if that's proven to have been to the detriment to the competition then I'm sure it will be left to the authorities. We just want people to enjoy the game.

"Of course it's a shame, for both of us - Mauricio wants to be talking about his team's quality.

"The focus comes away from what we've achieved in the competition. It's wrong in society and it's wrong in football."

Millwall are still under investigation from the Football Association after Leicester complained about the behaviour of the club's fans following their victory in the previous round.

There was a heavy police presence outside White Hart Lane before kick-off as supporters of both teams had to be separated from skirmishes while bangers, flares and bottles were thrown.

On the pitch, however, any tension quickly disappeared as Tottenham blew away their League One opponents with a clinical, attacking display.

The only blemish on Spurs' afternoon came through an injury to Harry Kane, who landed awkwardly on his right ankle after hurdling a challenge from Millwall's Jake Cooper.

Kane was substituted in the 10th minute and was later seen leaving the stadium on crutches and wearing a protective boot.

An injury to the same ankle caused the 23-year-old to miss seven weeks earlier in the season.

"He twisted his ankle, the same ankle that was before in the game against Sunderland. Now it's a matter of waiting," Pochettino said.

"We will assess tomorrow, and after tomorrow, and see what happens. It's difficult. It looks a similar situation to Sunderland, during that game, but we'll see. We need to wait and be positive."

Kane looks certain to miss next weekend's Premier League game at home to Southampton and is also a doubt for England's fixtures against Germany and Lithuania later this month.

Pochettino will hope Son can continue his form in Kane's absence while Janssen's goal was the Dutchman's first from open play since joining Tottenham last summer.

"We can't cry about it now. We have to be positive. We have players enough to try and replace him," Pochettino said.

"When you lose a player like Harry Kane, you know you'll miss him. But it's important for the players who play in his position, Son or Vincent today, to find the net and score goals.

"When we talk in the past about the squad, look now - now we need to see how they are important.

"Players like Vincent and Son, who haven't played in the last few weeks in the starting XI, may now be important for us."

Alli believes Tottenham's six goals emphasised the club's strength.

Alli told BBC One: "It is always horrible to lose a player like Harry, he's been in top form, but I think that shows our depth in quality and everyone stepped up a gear."