A Spanish newspaper says it will give a prosecutor documents that it claims shows Spain was a target for surveillance by the U.S. National Security Agency.

EL Mundo said Tuesday the prosecutor had sought the documents after the paper published photographs of them last week and alleged the NSA tracked some 60 million Spanish phone calls in one month alone and that Spain and other countries had cooperated with the NSA.

Allegations of NSA spying on allies have irked European countries. Spain insists it is unaware of any spying but demands an explanation from Washington. Spain's intelligence services chief is to give a closed-door briefing on the issue in Parliament Wednesday.

The NSA acknowledges European phones were monitored as part of a NATO program but insists it didn't act alone.