Ten mortars landed near Kerem Shalom crossing, a major passageway used by Israel to deliver humanitarian aid and fuel to the besieged territory, and a military site near the closed Kissufim crossing in southeast Gaza, said Palestinian security sources.
No injuries or damage were reported in the mortar attacks.
Following the incident, Radio Israel said that Kerem Shalom crossing was sealed off.
Meanwhile, the armed wing of the Popular Resistance Committees claimed responsibility for the attacks in a statement, saying the mortars came in response to an Israeli airstrike on Tuesday which killed and wounded a number of its fighters.
Witnesses said on Tuesday that the militants were trying to fire rockets into western Negev when an Israeli unmanned plane attacked them.
A militant died immediately in the aerial raid and another gunman died of his wounds on Wednesday, according to the organization.
Also on Thursday, Israeli planes dropped flyers in northern Gaza Strip, warning residents to stay away from an electric fence between the Hamas-controlled coastal Strip and Israel.
The leaflets, printed with telephone numbers and emails, urged people to inform the army of any activities of the Palestinian militants in the border area.