Funerals took place across Nicaragua on Friday for 16 people killed in one of the bloodiest days of protest in the country where weeks of anti-government demonstrations have left more than 100 dead.

There seemed little prospect of an early return to negotiations Friday between the government of President Daniel Ortega and the opposition after more than six weeks of near continuous protests.

Ortega has rejected calls to step down and the Catholic Church, which has tried to mediate the conflict, has refused to resume the talks for as long as government "repression" continues.

Hundreds of people packed into a church in Managua for the funeral of 14-year-old high school student Orlando Cordoba.

He was hit by a bullet while marching in a protest at the Central American University on Wednesday.

The teenager's body was draped with a blue and white scarf bearing the legend "Nicaragua Libre."

"Lord give me peace in my heart....I never expected this," his weeping mother Yadira Cordoba said as she clung to his coffin while it was being closed.

Similar emotional scenes were repeated at other funerals as victims were laid to rest after what protest umbrella group Civic Alliance described as the "worst massacre" since protests started on April 18.

Mediator gets 'death threats'

Silvio Jose Baez, the auxiliary bishop of Managua mediating the stalled talks, had received "death threats" and his life was in danger, the Inter-American Commission on Human Rights (IACHR) warned in a statement released in Washington.

"Massacre! Shots are being fired against peaceful demonstrators," Baez wrote on social media late Wednesday, the night of the Mothers' Day protests in which the latest round of killings took place.

The Nicaraguan Center for Human Rights said the killings occurred in the capital Managua and the cities of Esteli and Masaya, while incidents also took place in Leon.

"The aggressors were the repressive police and shock forces" who report to Ortega and his wife, according to the rights group.

The government and opposition had agreed on Monday to resume peace talks mediated by the Catholic Church that stalled last week.

But the Nicaraguan Bishops' Conference announced Thursday that it will not resume the dialogue as long as "the people continue to be repressed and killed" by "groups close to the government."

The head of the Organization of American States, Luis Almagro, on Thursday condemned the killings by "repressive forces and the armed forces," and called on Ortega's government to stop the violence.

The US State Department issued a statement condemning the "government's violent response to peaceful Mother's Day marches in Managua and other cities yesterday, including assaults on mothers mourning their children killed since protests began April 18."

Ortega decries 'conspiracy'

Ortega, meanwhile, denounced a "conspiracy" by the opposition aimed at "terrorizing" the people, referring to Wednesday's unrest.

"There are no shock forces or paramilitaries close to the government, so we cannot accept that we are accused of tragic and painful events that we have not provoked and we would never provoke," he said in a statement.

In its statement in Washington, the IACHR said it had received reports that Bishop Baez and his relatives "are on a list of people who need to be 'wiped out' and that suspicious persons are constantly watching his family home."

"The Commission has been able to check pictures that show, on Facebook, not only various messages to discredit Silvio Jose Baez Ortega -- which in this specific context create a particularly hostile atmosphere against the beneficiary -- but also photos that concretely show a person who had allegedly threatened to kill the auxiliary bishop, with a firearm."

"The Commission also noted the intimidating effect that such a situation could have on his own and other participants' involvement in the ongoing talks."