Updated

Tens of thousands of Nicaraguans have joined one of the largest marches to date in weeks of protests against a government crackdown on dissent.

The protesters in the capital called for an investigation into those killed in previous weeks and a halt to actions against demonstrators.

Referring to the dead, participants in Wednesday's march chanted, "They were students, not criminals!"

Human rights groups say 63 people were killed when police and Sandinista youth groups allied with the government violently repressed protests last month against a social security overhaul.

Accountant Alberto Ramirez participated in the latest march, which included farmers, businessmen and students. He said President Daniel Ortega "should understand we are not afraid."

Supporters of Ortega held a concert in another part of the city.