Nicaraguan government negotiators have signed an agreement ratifying their commitment to free hundreds of people considered political prisoners by the opposition.

The document signed in talks with the Civic Alliance opposition group on Friday calls for the International Red Cross to propose an updated list of prisoners who should be freed by mid-May.

The opposition says more than 640 people have been jailed for political causes since protests broke out in April against the government of President Daniel Ortega. The government says the actual numbers are far smaller.

The Inter-American Human Rights Commission says 325 people have died in the protests and more than 50,000 have fled the country.

The government also said it would drop charges against many people facing arrest warrants, including some who had fled abroad.