The Israeli air force carried out strikes on Hamas sites in Gaza early Thursday in response to a rocket attack targeting the Jewish state, the army and Palestinian sources said.

The rocket, which hit an open area in southern Israel, caused no damage or casualties. 

In response, the Israeli air force "targeted two Hamas sites in the southern Gaza Strip," the military said in a statement.

According to the army, nine projectiles fired from the Gaza Strip -- which is run by Islamist movement Hamas -- have hit Israel since the start of 2016.

No Palestinian group claimed responsibility for Thursday's rocket attack, which came hours after Israeli Prime Minister Benjamin Netanyahu sealed a deal to bring hardline nationalist Avigdor Lieberman into his coalition.

Outspoken Lieberman, who is set to become defence minister, has over the years threatened action on Gaza and its Hamas rulers.

He recently said that if he became defence minister, he would give Hamas's Gaza leader Ismail Haniya 48 hours to return detained Israelis and soldiers' bodies "or you're dead".

In its statement the Israeli army repeated its policy of holding "Hamas accountable for all attacks emanating from the Gaza Strip."

Palestinian security officials said the Israeli raids targeted Hamas military sites in Nuseirat and Rafah, causing no casualties.

The latest exchange of fire follows four days of cross-border violence earlier this month -- the worst since the 2014 Gaza war that killed 2,251 Palestinians and 73 Israelis.

The United Nations envoy for the Middle East warned the Security Council on Wednesday of a "highly volatile" situation in Gaza.

"Palestinians in Gaza are growing ever more desperate, seeing their prospects for living a normal life and recovering their economy blocked by Hamas's military build-up, by Israel's security measures and closures, by the lack of Palestinian unity, and the insufficient fulfilment of aid pledges by donors," Nickolay Mladenov said.

"Recent events clearly demonstrate that the spectre of violence looms ominously over the territory," Mladenov said.

"Unless radically more is done to address the chronic realities in Gaza, it is not a question of 'if', but rather of 'when' another escalation will take place."

Source: AFP