London - The English Football Association apologised on Monday over a mischievous tweet about Tottenham Hotspur's Harry Kane during the weekend FA Cup semi-final against Manchester United.

The 24-year-old failed to fire in Saturday's 2-1 loss to United which was largely down to a fine performance by central defender Chris Smalling in keeping Kane quiet.

That prompted a tweet on the official FA account: "What's in your pocket, Chris" and a video of United defender Chris Smalling saying "Harry Kane".

The tweet was shared thousands of times before it was deleted.

"We have written to both clubs to apologise for any offence caused," a FA spokesperson said.

Kane is likely to start up front for England at the Soccer World Cup.

He could end up captaining the national side at the finals in Russia in June and what made the tweet even more ironic is Smalling was dropped by England manager Gareth Southgate last November because he didn't rate his ball passing skills.