GENEVA (Reuters) - U.N. aid agencies on Tuesday voiced alarm at the scale of the ongoing operation in the West Bank town of Jenin, where ten Palestinians have been killed, and said there were restrictions on medical access.

"We are alarmed at the scale of air and ground operations that are taking place in Jenin in the occupied West Bank, and air strikes hitting a densely populated refugee camp," Vanessa Huguenin, a spokesperson for the U.N. humanitarian office, told a briefing, saying three minors were among those killed.

She did not immediately respond to a request for comments on the ages of the victims.

"First responders have been prevented from entering the (Jenin) refugee camp, including to reach persons who have been critically injured," said WHO spokesperson Christian Lindmeier, referring to restrictions put in place by Israeli forces.

Medical charity MSF said in a statement on Tuesday that military bulldozers had destroyed roads leading to the camp, making it nearly impossible for ambulances to reach patients. "Palestinian paramedics have been forced to proceed on foot, in an area with active gunfire and drone strikes," it said.

Israel says the objective of its operation is to uproot Iranian-backed Palestinian factions behind a surge in gun and bomb attacks as well as preliminary efforts to make rockets.

(Reporting by Emma Farge; editing by Matthias Williams and Rachel More)