GENEVA (AP) — The U.N.'s human rights office says three men recently sentenced to death in the Palestinian territory of Gaza were executed unlawfully.

A spokesman for U.N. High Commissioner for Human Rights Navi Pillay says the men didn't have regular access to lawyers and were tried by a military court despite being civilians.

Rupert Colville told reporters in Geneva that the death sentences carried out by hanging April 7 also weren't approved by Palestinian President Mahmoud Abbas as required by law.

The U.N. rights office is calling on Gaza's ruling Hamas faction to halt a planned execution by firing squad.

At least 18 men have been executed in Gaza since Hamas seized power there in 2007.

The Palestinian Authority effectively halted the practice in the West Bank in 2004.