The U.N.'s Mideast envoy said Saturday he was "alarmed" by Israel's decision to resume house demolitions in the West Bank.

Earlier this week, Israel knocked down dozens of shacks in two West Bank villages, leaving dozens of Palestinians homeless.

U.N. envoy Robert Serry said Israel agreed in April to halt the demolitions and he urged it to reinstate the moratorium.

Israel's actions "send a discouraging signal" about Israeli support for efforts to improve living conditions in the West Bank and to build Palestinian backing for peacemaking, Serry added in a statement.

Israeli Foreign Ministry spokesman Yigal Palmor said at least some of the houses were built illegally on public land.

"The fact that the U.N. continues to ignore the specific circumstances of each case and prefers to express generalized criticism makes these statements very unhelpful," Palmor said.