Violations of the Geneva Conventions adopted in 1949 following World War II are commonly called "war crimes".
Protests intensified on the 70th anniversary of Israel's founding, as loudspeakers on Gaza mosques urged Palestinians to join a "Great March of Return".
Dozens of Palestinian demonstrators broke into the Gaza side of the terminal on Friday, setting a pipeline that delivers gas from Israel alight and torching a goods conveyor belt.
Asked what he wanted to see from protests on Monday and Tuesday, Hamas official Yahya Sinwar pointed out Israel has never specifically defined its borders.
Palestinian health officials said the two men had been killed by Israeli gunfire near the town of Khan Younis.
Tunisia on Wednesday announced the arrest of a suspect in the murder of an aerospace engineer described by Palestinian movement Hamas as one of its members.
A spokesman for the Hamas-controlled territory's health ministry named the latest fatalities as Tahrir Wahada, 18, and Abdullah Shamali, 20.
Hamas, which rules the Gaza Strip, accused Israel's Mossad spy agency of assassinating Fadi al-Batsh, who they say was a member of their group.
Israel's defence minister said on Sunday a Palestinian scientist shot dead in Malaysia was a rocket expert and "no saint", but dismissed suggestions by Hamas that Israel's Mossad spy agency assassinated him.