The Israeli soldier was killed on Wednesday in the West Bank during a military operation, the Israeli army said.
Aljazeera's correspondent in Palestine quoted Izz al-Din al-Qassam Brigades of Hamas as claiming responsibility for the Israeli soldier's killing in the village of Mirka, south of Jenin.
A Hamas spokesperson said fighters ambushed an Israeli security patrol in the area and may have killed one of the soldiers.
The Israeli occupation forces arrested two brothers who are Hamas activists and imposed a curfew on the village for several hours before withdrawing.
On Tuesday, six passers-by were injured when an unmanned Israeli aircraft fired a missile into a car on the move near the Jabaliya refugee camp in Gaza.
Hassan al-Madhun, 32, a local leader of the Nabil Masud Brigades, an armed wing of the Al-Aqsa Martrys' Brigades, was killed, security sources said.
Israeli occupation army used at
least 40 military vehicles in Jenin
The other victim was identified as Fayiz Abu al-Qaraa, 37, a local leader of the Iz al-Din al-Qassam Brigades, Hamas's military wing.
Aljazeera's Gaza correspondent Wail al-Dahduh reported both al-Madhun and al-Qaraa were driving towards al-Falluja district in Jibalia, north of Gaza when they were attacked by an Israeli drone.
Witnesses said the Israeli military drone fired two or three rockets at the car which was destroyed, killing the two Palestinians.
Hamas vowed to retaliate against Israel's military operations and assassinations saying Israel has declared war by carrying out these operations.
A senior Hamas official told AFP "Israel has started a war" by killing the two men.
"Israel has started a war with this assassination and it will pay a heavy price," he said speaking on condition of anonymity.
Saeb Erikat has condemned
Israeli military incursions
"This assassination will open the gates of hell on the enemy," Islamic Jihad said after Tuesday's strike.
Al-Aqsa Martyrs' Brigades said after Israel's missile attack that it had ordered all its fighters "to strike the enemy everywhere".
Islamic Jihad had expressed a readiness on Sunday to maintain the truce agreed upon and suspend operations if Israeli air raids stopped, but Israeli officials pledged to press ahead with a military campaign against Palestinian resistance groups.
Palestinian chief negotiator Saeb Erikat said the Palestinian Authority (PA) was "exerting maximum efforts" to persuade all the groups to cease their attacks.
"And now this happens. It is like pouring oil on the fire," he said, condemning the Israeli strike.
"Israel has started a war with this assassination and it will pay a heavy price"
Senior Hamas official
In another incident, fierce clashes erupted in the northern West Bank city of Jenin late on Tuesday as at least 40 Israeli tanks and Jeeps converged on the city, Palestinian security sources and witnesses said.
Two Palestinians were wounded while troops arrested Adib Abu Hussein, 30, a local chief of Al-Aqsa Martyrs' Brigades, which is loosely affiliated with Palestinian leader Mahmoud Abbas's Fatah party.
A leaders of al-Quds Brigades, Salih al-Saadi, however managed to escape.