An opposition group says Nicaraguan police have arrested anti-government demonstrators and says three were wounded by gunfire just a day after official negotiators promised to release people detained in earlier protests.

The National White and Blue Union says riot police arrested 10 demonstrators at a shopping center and that at least three people were wounded by gunfire aimed at protesters Saturday. It says another protester was arrested in the city of Leon.

A day earlier, negotiators for President Daniel Ortega signed agreements ratifying commitments to release and drop charges against hundreds of people considered political prisoners by the opposition. They also promised freedom to demonstrate.

The opposition says more than 640 people are being held for political causes, jailed in protests that broke out in April against Ortega's government.