RAMALLAH (Reuters) - An Israeli air strike killed two Palestinian militants in the city of Tulkarm on Monday, Hamas said, underscoring Israel's renewed focus on armed groups in the occupied West Bank since the start of the ceasefire in Gaza.

Hamas, the Palestinian militant group that controls Gaza, said the two killed on Monday were members of its armed wing. Witnesses in the city said a raid was underway but there was no immediate comment from the Israeli military. The Palestinian health ministry confirmed that two people had been killed, without identifying them.

In Jenin, further north, a major operation with hundreds of Israeli troops backed by armoured vehicles, drones and helicopters, looked set to go into a second week, with smoke rising above the refugee camp adjacent to the city, a longtime centre of armed militant groups.

Armoured bulldozers and diggers have destroyed buildings and roads in the camp, a crowded township built for descendants of Palestinians who fled or were forced from their homes in the 1948 war around the creation of the state of Israel, and thousands of people have left their homes.

At least 16 Palestinians have been killed in Jenin and surrounding areas since the start of the operation a week ago, including four claimed as fighters by Hamas and the Iranian-backed Islamic Jihad.

Late on Saturday, Israeli forces also shot a two-year old girl during a raid on the village of Ash-Shuhada, just to the south of Jenin, Palestinian officials said.

"They started to shoot at us through the windows without any warning," said Ghada Asous, grandmother of two year-old Laila Muhammad Al-Khatib. "All of a sudden, the special forces raided us and were shooting through the windows."

The Israeli military (IDF) said troops on a counterterrorism operation had fired at a structure where suspected militants had barricaded themselves.

"The IDF is aware of the claim that uninvolved civilians were injured as a result of the fire. The incident is under review," it said in a statement.

(Reporting by Ali Sawafta, writing by James Mackenzie; Editing by Hugh Lawson)