The Israeli air force carried out four strikes on militant targets in the Gaza Strip early Wednesday, eyewitnesses said, hours after a cross-border rocket attack on the Jewish state.
The planes targeted training camps belonging to militant group Islamic Jihad in Rafah, Khan Yunis and Gaza City, the witnesses said. There were no immediate reports of casualties.
A rocket fired from the Palestinian enclave struck southern Israel late Tuesday, causing no casualties or damage.
The Israeli army said it struck "four terror infrastructures in the southern Gaza Strip" in response.
Defence Minister Moshe Yaalon said Tuesday's rocket attack had been carried out by militant group Islamic Jihad.
"If we don't have calm in Israel, the Gaza Strip will pay a heavy price," he said in a statement.
"I do not advise anyone to put this to the test. Israel will not sit back after its citizens were targeted by Islamic Jihad," he added.
Nobody has claimed responsibility for the rocket attack.
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Israeli Prime Minister Benjamin Netanyahu said in a statement that his forces would "do whatever is needed to maintain calm" along the border with Gaza.
The Arab League condemned the Israeli air strikes.
"The extremist Israeli government is trying to find pretexts to divert the international community's attention from resuming (peace) negotiations," Arab League deputy head Ahmed bin Heli told reporters in Cairo.
The talks fell apart in April 2014, and prospects for their renewal seem bleak with a lack of trust between the sides exacerbated by the formation of Netanyahu's new hardline coalition.
Tuesday's rocket was the third fired from Gaza since the ceasefire ending the 50-day conflict in summer 2014, which killed about 2,200 Palestinians, most of them civilians, and 73 on the Israeli side, most of them soldiers.
Two mortar rounds were also fired at Israel since September, according to the Shin Bet internal security agency.
Wednesday's air strikes were the third time Israel targeted Gaza since the end of the 2014 war.
Last month, Israeli tanks fired at a Hamas position following a rocket attack.