Hamas authorities in Gaza on Tuesday executed three men for murder, the attorney general said, according to AFP.

The three, who were not named and whose cases were unrelated, were put to death by firing squad behind closed doors, security sources said.

The Palestinian Center for Human Rights (PCHR) said, however, that two of them were hanged and the third was shot.

Hamas officials said last week they were planning a series of public executions in the Gaza Strip, and it remains unclear whether Tuesday’s executions – which as mentioned were done behind closed doors – were related.

“To achieve public deterrence and curb crime, the competent authorities carried out at dawn on Tuesday, May 31, 2016 execution rulings against three of those convicted of shocking murders,” a statement from the attorney general quoted by AFP said.

Rupert Colville, spokesman for the UN High Commissioner for Human Rights, condemned the executions which he said occurred “despite serious and widespread concerns that international fair trial standards were not respected”.

The UN’s Middle East envoy, Nickolay Mladenov, last week expressed alarm over the planned public executions and urged Hamas to change course.

“I urge Hamas not to carry out these executions and call on President Abbas to establish a moratorium on the implementation of the death penalty,” Mladenov told the Security Council by video-conference.

The European Union, Human Rights Watch (HRW) and Amnesty International all also condemned the killings, noted AFP.

In theory all execution orders in the Palestinian Authority’s territories must be approved by Palestinian Authority (PA) chairman Mahmoud Abbas, who is based in Ramallah.

But Hamas, which runs Gaza, no longer recognizes his legitimacy, and authorities have announced they are planning to carry out a series of public executions despite the moratorium on executions that Abbas announced several years ago.

In fact, Hamas emphatically declared last week that the death penalty in Gaza can be carried out without the consent of Abbas.

The UN statement said that the failure to get Abbas’s backing for the executions was a breach of Palestinian law.

According to the Palestinian Center for Human Rights, nine death sentences were handed down in Gaza in 2015 and two in the PA-assigned areas of Judea and Samaria. So far this year, around 10 more have been handed down in Gaza.

Amnesty International has previously called on Hamas to stop the executions of suspected collaborators, saying that the group “must immediately and totally cease its use of the death penalty.”