Israeli warplanes launched three strikes early on Sunday on the Gaza Strip, targeting radical Palestinian group Islamic Jihad but causing no casualties, witnesses said.
Two air strikes hit the southern town of Khan Yunis, targeting positions of the Al-Quds Brigade, the armed wing of Islamic Jihad. The third was near the southern town of Rafah straddling the border with Egypt, the Palestinian witnesses said.
An Israeli military spokeswoman confirmed the air force had carried out strikes on Gaza, but told AFP she could not give any further details.
The Israeli authorities on Sunday also closed the Kerem Shalom goods crossing until further notice after a rocket attack, the defence ministry said.
Prime Minister Benjamin Netanyahu told Sunday's weekly cabinet meeting that Israel would retaliate with great force against any rocket or missile fire.
"I want to make it clear that we will respond in a very offensive way against any rockets or missiles. We will take all necessary measures to ensure the security of Israelis... on all fronts," his office quoted him as saying.
Israel had not carried out air raids on Gaza since early April, when it launched the first strikes since a truce brokered by Egypt in November ended a deadly eight-day conflict between the Jewish state and militants of Islamist movement Hamas, which rules the territory.
On April 19, two rockets fired from Gaza hit southern Israel without causing casualties or damage.