Vincent Janssen
Vincent Janssen's second-half penalty helped the Netherlands secure a 2-1 victory over England in MarchGetty Images

Tottenham Hotspur will have to considerably up the ante in their pursuit of Vincent Janssen after AZ Alkmaar confirmed that they have rejected another bid for the Dutch forward. Spurs' interest in pursuing the addition of at least one new striker in order to provide adequate cover for Harry Kane is well established, with AS Roma's Antonio Sanabria also believed to be among their list of targets.

A potential deal for Janssen still appears to be some way off, however, with reports from De Telegraaf suggesting that Tottenham's third offer for the 22-year-old – which would have seen the Premier League club pay a fee of approximately €14m (£11.3m, $15.4m) spread over three years – has been turned down.

"The difference between the offer and the price we demand was too big," said technical director Max Huiberts, who is said to want at least €20m in exchange for a highly-rated young talent whose 27 goals in 2015/16 made him the Eredivisie's top scorer.

The 22-year-old has also netted three times in his first five senior international caps for the Netherlands, including a penalty in March's 2-1 friendly victory over England at Wembley.

Tottenham are not the only club tracking Janssen, with Wolfsburg sporting director Klaus Allofs admitting during an interview with German magazine Kicker last week that the Bundesliga outfit have also spoken to the player. Despite that, however, Huiberts insists that Tottenham are thus far the only suitor to have made an official move for his services.

"I've read a lot of speculation and been telephoned by other clubs but no-one else has made any concrete offer," he added.

Janssen, who cost AZ just £400,000 from Almere City in 2015, is already believed to have met with Tottenham in London. Mauricio Pochettino has been active in the transfer market this week and On Thursday (23 June) secured his first signing of the summer with the addition of Southampton's Victor Wanyama for an undisclosed fee believed to be in the region of £11m.

In switching to north London, the powerful midfielder reunites with the manager responsible for making him the first Kenyan export to the Premier League following his move from Celtic in 2012. Tough-tackling Wanyama made 97 appearances in all competitions for the Saints and last season became only the seventh player ever to be sent off three times in the same top-flight campaign.