The attack occurred at the Erez crossing on Israel's border with the Gaza Strip, the army said. One soldier was in moderate condition, while the others were lightly wounded, the army said.
The attack came shortly Prime Minister Ehud Olmert said he would not negotiate a cease-fire with Palestinian militants firing rockets.
On Saturday, the Hamas militant group said it would consider a one-year cease-fire with Israel, but only if Israel halts military activities in Gaza and the West Bank.
A Hamas-affiliated radio station said Hamas militants carried out Sunday's attack.