JERUSALEM, Oct. 18 — Israeli troops uncovered five smuggling tunnels today as the forces advanced along the Gaza Strip’s southern border with Egypt, and four Palestinians were killed in overnight clashes, according to the Israeli military and Palestinian security officials.

Over the past week, the Israeli forces have staged almost daily raids in Gaza, and more than 25 Palestinians, most of them Hamas militants, have been killed.

“We have no intention of going back and controlling Gaza,” the Israeli defense minister, Amir Peretz said in Parliament. “But we are obligated to provide security for the citizens of Israel. We will not make a policy of closing our eyes to the smuggling.”

The Palestinian Authority denounced the Israeli military action, calling it a “criminal escalation that is reaching all cities and villages.”