Israel's military said soldiers opened fire on Thursday after spotting two Palestinian gunmen near the Gaza border fence, and the Hamas militant group said one of its fighters was killed.
The last round of violence in the Gaza Strip and neighboring southern Israel was in May, with hundreds of Palestinian rocket attacks and Israeli airstrikes over three days.
The health ministry in Gaza, an enclave run by Hamas militants, said 28-year-old Palestinian Mahmoud al-Adham was shot and killed in Thursday's incident near Beit Hanoun in the northern part of the territory.
The Israeli military says it noticed two "armed suspects" near the Israel-Gaza perimeter fence and "fired in order to drive them away".
Gaza's Health Ministry said al-Adham was wounded in his leg and died later at the hospital.
In a statement, Hamas's armed wing said Israeli forces deliberately targeted a fighter "on duty" near the border. It vowed to retaliate.
"The occupation bears responsibility for the consequences of such a criminal act," it said, referring to Israel.
After May's fighting, there was a ceasefire brokered by Qatar, Egypt, and the United Nations.
But tensions have remained high, with Hamas accusing Israel of failing to abide by the terms - never publicly confirmed by Israeli leaders - of a truce deal to ease a blockade of Gaza.
