MADRID (REUTERS) - Johan Cruyff, one of the greatest footballers and most influential coaches, has been diagnosed with lung cancer, according to reports in Spanish media on Thursday.

His foundation could not immediately confirm the reports of his illness but said they were planning to publish a news release later on Thursday.

Cruyff had been diagnosed with the illness this week at a clinic in Barcelona and was having tests to determine the seriousness of his condition, according to the reports, which did not identify the source of the information.

The 68-year-old, who won the Ballon d'Or three times, helped Ajax win three European Cups in a row in the early 1970s before joining Barcelona and leading the Catalan club to their first La Liga title in nearly 15 years in 1974.

After stints at other clubs including Los Angeles Aztecs, Washington Diplomats and Levante, Cruyff returned to Ajax before ending his playing career at bitter rivals Feyenoord.

Cruyff also led the Netherlands, playing the "Total Football" he would later refine and make his own as a coach, to the 1974 World Cup final, where they lost 1-2 to West Germany.

In 1999, Cruyff was voted European Player of the Century.