Two Israelis have been killed in a blast thought to have been caused by a homemade rocket fired by Palestinian militants from the Gaza Strip.
The Bedouin Arab shepherds killed by rockets were father and son
The explosion occurred near Nahal Oz farming community just a few hundred metres east of the Gaza Strip.
Israeli medics said the two casualties were Bedouin Arab shepherds.
In other violence, as Israelis vote in a closely-watched general election, Israeli troops killed one Palestinian militant in a raid in the West Bank.
Samer Freihat, 24, was hit by an Israeli bullet after clashes broke out in the village of Yamun, near Jenin, Palestinian medics said.
Palestinian radio said he was shot several times and left to bleed for several hours before he died.
An Israeli army spokesman said troops had opened fire after seeing Freihat was armed, adding that he had been on a list of wanted militants.
Samer Freihat was shot during an Israeli raid on Yamun village
In Gaza the Islamic Jihad militant group claimed responsibility for the Nahal Oz blast - which killed a father and his 16-year-old son - saying it had timed a rocket attack to disrupt the election in Israel.
The Israeli army said the explosion might have been caused by a rocket that had lain dormant for some time.
However, the army did confirm that three rockets had been fired from Gaza during the day.
Palestinian militants frequently fire makeshift rockets from the Gaza Strip, but only rarely to they cause Israeli casualties and often the explosives are not detonated on impact.
Tuesday's victims were Bedouin Arabs, who make up about 10% of Israel's Arab community, which itself represents about one-fifth of Israel's total population.