Two members of the al-Quds Brigades, the military wing of Islamic Jihad, were killed when Israeli soldiers opened fire in the Gaza Strip.
It happened near the Israeli border, close to Khan Younis, on Sunday morning. Israel says the men were planting explosives.
Israel has launched multiple air raids aimed at what they say are Hamas facilities over the past week.
Hamas's military wing has accused Israel of "playing with fire".
Fighters in Gaza have fired back at Israel, with about 30 rocket attacks into southern Israel over the past few weeks.
Al Jazeera's Sherine Tadros reports on rising tension, ahead of the second anniversary of Israel's war on Gaza.