At least four Palestinians have been killed in the Gaza Strip as Israeli troops, backed by tanks, stepped up their offensive operations in the territory. Wednesday's Gaza incursion follows an Israeli military operation, Tuesday in the West Bank, in which five Palestinians were killed.

Palestinian woman searches for her brother, suspected member of Al-Aqsa Martyrs Brigades, among Israeli armored vehicles, Wednesday Oct. 18, 2006

Israeli troops and tanks pushed into Rafah, near the Gaza Egypt border, in an operation designed to destroy tunnels that Israel says are being used by Palestinian militants to smuggle weapons into the Gaza Strip.

Major Avital Leibovich, a spokeswoman for the Israeli Defense Forces, says two tunnels were found in the current operation, adding to a large number discovered in recent months.

"So far we managed to uncover 15 tunnels, which is a huge number. Imagine the amount of ammunition being able to be transferred through these tunnels," she said.

Palestinians have condemned Israel's military incursions in Gaza, which began in late June, after Palestinian militants abducted an Israeli soldier from a Gaza border post.

Israel says the incursions will continue as long as their soldier is held and as long as Palestinian militants launch rockets from Gaza into southern Israel.