A U.N. expert on the human rights of Palestinians has submitted his resignation, complaining that Israel didn't grant him access to the Palestinian territories.

The U.N. human rights office said Monday that Makarim Wibisono, the special rapporteur on the situation of human rights in the Palestinian territories, will step down March 31.

Wibisono, who took the post in mid-2014, said he accepted it "with the understanding that Israel would grant me access, as an impartial and objective observer" but his efforts were "frustrated every step of the way." He added that repeated requests for access, both orally and in writing, were unsuccessful.

Israeli Foreign Ministry spokesman Emmanuel Nahshon noted Wibisono wasn't the first person to resign the post. He said the mandate given to the rapporteur is "distorted and biased."