Israel is continuing its military operation in Gaza to uncover and destroy tunnels it says are being used to smuggle weapons from Egypt. The United Nations has condemned the killing of at least seven Palestinians by Israeli troops in the raid, which began on Friday.

Israeli troops on Saturday uncovered another tunnel in the Palestinian Rafah refugee camp, connecting Gaza to Egypt. They also blew up one of two other tunnels found during searches on Friday.

The military mission, codenamed Operation Root Canal, is meant to expose and seal all such tunnels, which Israel claims are being used to deliver arms to Palestinian militants in the Gaza Strip.

A number of Palestinians have been killed and dozens more wounded in the exchanges of gunfire between the soldiers and Palestinian gunmen.

A spokesman for Palestinian President Yasser Arafat condemned the Israeli operation as a war crime.

United Nations Secretary-General Kofi Annan has also condemned what he described as Israel's disproportionate use of force in heavily populated areas and called on both sides to take all necessary measures to stop civilians being harmed.

Israel says it was acting on intelligence information that Palestinian militants were seeking to smuggle shoulder-fired missiles from Egypt.

Experts say such weapons could be used to destroy tanks and bring down helicopters, Israeli fighter jets and even civilian aircraft flying over the Gaza Strip.

Israeli officials said the Palestinians were also trying to smuggle Katyusha rockets which have the range to reach Israeli cities close to the Gaza Strip.

One military commander involved in the operation says there are fears that such weapons could eventually be brought to the West Bank and used by Palestinian militants to launch attacks against other parts of Israel.