Hundreds of Nicaraguans opposed to President Daniel Ortega took to the streets of the capital Managua on Wednesday in protests deemed illegal by the government and several dozen were arrested, according to an opposition group.

Nicaragua's National Police said in a statement that one person was killed in the "crossfire" between demonstrators.

At least six people have died since Nicaraguans began demonstrating on Wednesday against measures that increase worker contributions and lower pensions, in an unusually direct challenge to Ortega, a former Marxist guerrilla.