The latest air strikes come despite an Israeli announcement of resumption of Qatari aid to Gaza, a move seen as bolstering a fragile Egyptian-mediated truce to the May fighting.
Israeli warplanes have bombed Hamas sites in Gaza overnight, Israeli military said as tension remained high after cross-border gunfire seriously injured an Israeli soldier on Saturday.
There were no immediate reports of casualties in the air strikes that targeted what the Israeli military claimed was a weapons production facility and a rocket launch site belonging to Hamas.
The strikes were carried in response to so-called incendiary balloons launched from the Palestinian enclave, Israeli military said.
Cross-border violence has spiked despite an Israeli announcement last week of a resumption of Qatari aid to Gaza, a decision that had been seen as bolstering the fragile truce.
'Israel tries to cover up its failure'
Hamas spokesman Fawzi Barhoum said on Saturday's air strikes showed Israel was "trying to cover up its failure and disappointment in front of the steadfastness of our people and their valiant resistance."
Confronting Gaza protesters along the border on Saturday, Israeli troops shot and wounded 41 Palestinians, critically injuring two, medics said. Palestinian gunfire seriously wounded an Israeli soldier, the military said.
It was the first confrontation since the May 21 ceasefire.
More than 250 Palestinians were killed in the May conflict, during which Israel carried out air strikes across the coastal enclave.
Israel keeps Gaza under blockade, tightly restricting movement out of the territory that is home to two million Palestinians. Egypt also maintains restrictions on the enclave. Both cite threats from Hamas for the restrictions.