The execution in the Gaza Strip of three Palestinians accused by Hamas of collaborating with Israel has been condemned "in the strongest terms" by the UN human rights office.

Spokeswoman Ravina Shamdasani said the executions happened despite international appeals to block the sentences and violated "Palestine's obligations under international law".

The rights office said the convictions were delivered for treason, which does not qualify among "most serious crimes".

It noted the defendants were civilians convicted by a military court, "again in contravention of international law".

The office said the trial did not appear to meet fair trial standards.

The three were sentenced months ago for relaying information to Israel, before last month's killing of a Hamas senior commander, Mazen Faqha.

PA