Israeli troops killed a Palestinian in Gaza, medics said.
The army said the man had been trying to launch a missile at a nearby Jewish settlement. Soldiers then fired at the device, causing it to explode near him, a spokesman said.
Earlier, soldiers say they opened fire on a Palestinian youth at dawn on Friday when they spotted him crawling towards the fence protecting Ghany Tal, which lies opposite the Palestinian city of Khan Yunus, inside the Gush Katif settlement bloc.
Aljazeera's correspondent in Gaza said that witnesses saw fierce clashes between Palestinian resistance fighters and Israeli occupation forces stationed at a military watch tower.
Israeli radio has named the 18-year-old as Muhannad al-Nahaal.
An Israeli spokesman said no weapons were found on his body.
Meanwhile, an Israeli was killed in a shooting attack as he was driving near Nablus in the northern West Bank, Israeli military sources said.
One Israeli was killed and three
others wounded in the attack
Two other Israelis were seriously wounded in the attack and were evacuated by helicopter from the site of the incident.
Israeli military and medical sources also reported that a fourth Israeli was slightly wounded in the attack.
On Thursday, Hamas fighter Muhammad al-Laham, 18, was killed as he tried to enter Ghany Tal.
The Israeli army said it had launched a manhunt for an accomplice.
The latest death brought the overall toll since the September 2000 start of the Palestinian Al-Aqsa Intifada to 4673, including 3628 Palestinians and 970 Israelis.