Warsaw  - Lech Walesa, one-time leader of the Solidarity trade union, demanded an apology from Polish President Lech Kaczynski for saying Walesa been a secret agent in communist Poland.

Walesa wrote an open letter to the president and gave him one week to apologize for comments Kaczynski made in a TV interview on June 4. During his appearance on TV Polsat, Kaczynski had said, "I know he was an agent with the pseudonym 'Bolek.'"

Walesa wrote it wasn't the first time Kaczynski had violated his personal rights, and said he'd won prior court cases that cleared him of such charges. He told the daily Dziennik that unless he receives an apology, he will look into having Kaczynski removed from office.

"I believe history will reveal the truth," Walesa wrote. "The world has recognized my efforts and struggles, and you are demeaning yourself and the Polish people."

A soon-to-be released book by historians of the Institute of National Remembrance is said to contain details on Walesa's alleged dealings with communist secret services.

Kaczynski said the book shows the truth about certain aspects of Walesa's life, reported the daily Wyborcza. Walesa, however, said in a TV interview on Monday that he knows who "Bolek" is, and will reveal his true identity after the book is published.

Walesa is a Nobel Peace Prize winner and former leader of the Solidarity movement that challenged Poland's communist regime in the 1980s. (dpa)