Poland's bishops are acknowledging that they have not done enough to prevent clerical abuse of minors and say there are "no words" to describe their shame about sex scandals involving priests.

The acknowledgement on Wednesday comes as Poland, a country where Catholic traditions and faith remain strong, is grappling with the problem of abuse. The debate was triggered by a documentary, "Tell No One," that was released on YouTube this month and already has 21 million views.

The primate of Poland, Archbishop Wojciech Polak, told reporters in Warsaw that the Polish Bishops' Conference met to discuss the problem and prepared a letter to be read out in all churches on Sunday. The letter begins: "There are no words to express our shame because of sexual scandals involving clerics."