Nicaragua resorted to a "shoot to kill" strategy to repress recent anti-government protests, human rights group Amnesty International said in a report released in Paris Thursday.

Speaking of the deaths of more than 70 demonstrators during anti-government protests in different parts of the Central American country in April and May 2018, Amnesty said the "alarming number (...) indicates there was an intention to shoot to kill on the part of the security forces."

Nicaragua's ambassador to France, Ruth Esperanza Tapia Roa rejected Amnesty's report as "baseless", in comments to AFP.

Nicaragua's descent into chaos began on April 18 when the police and pro-government paramilitaries cracked down on protests against social security reforms.

Demonstrations evolved into a wider opposition against President Daniel Ortega, a former leftist guerrilla in power for 11 years who has refused calls to step down.

Rights groups say over 300 people have now been killed in the turmoil and hundreds more detained in a crackdown.

Ortega has dismissed UN charges of a disproportionate use of force against protestors, enforced disappearances and torture.

He called the United Nations a tool of "lies and infamy", and last month expelled the UN rights mission after it published a report criticising the "climate of fear" in the country.

Amnesty said its investigative team found evidence of extrajudicial executions during the first weeks of the protests.

"Most of the fatalities during the protests were the result of firearm injuries, despite the fact that the use of such lethal weapons by state officials should only be authorised in the most extreme situations," the report said.

Amnesty specifically looked into nine of the killings and found that "the point of entry of bullets indicates that in many cases people were hit in parts of the body where the injury was most likely to prove fatal, indicating that there was an intention to shoot to kill."

Snipers are believed to be responsible for some of the deaths in the capital Managua and cities of Leon, Ciudad Sandino and Esteli, Amnesty said.

Authorities refused at times to carry out autopsies, attempted to prevent families from making official complaints, and clamped down on the press, it added.

A number of other international human rights organisations have spoken out against the ongoing crackdown in Nicaragua.

These include the Inter-American Commission on Human Rights and four special rapporteurs from the Office of the United Nations High Commissioner for Human Rights.