Spanish political parties say they are happy that Spain's secret service is operating lawfully, but are still waiting for the United States to provide explanations for allegations that its National Security Agency carried out surveillance in the country.

National Intelligence Center chief Felix Sanz Roldan spoke in a closed-door session to a parliamentary commission Wednesday and made no public comments, but opposition Socialist party spokeswoman Soraya Rodriguez said he convinced her that Spain's secret service is acting lawfully.

She said the U.S. must now offer explanations, as Spain has demanded.

El Mundo newspaper recently published leaked NSA documents allegedly showing the agency tracked Spanish phone calls and that Spain and other countries helped the NSA monitor communications.

The NSA acknowledges phones were monitored but insists it didn't act alone.