Israel's military struck several Hamas positions in the Gaza Strip on Wednesday after a rocket launched from the Palestinian enclave hit a nearby Israeli city, with no casualties reported on either side.

The rocket hit Sderot, part of which lies less than a kilometre (less than a mile) northeast of the Gaza Strip, run by Islamist movement Hamas, the Israeli military said.

The area was closed off and bomb disposal teams were working at the site, police spokesman Micky Rosenfeld said.

A small Salafist group -- followers of an ultra-conservative brand of Sunni Islam who oppose Hamas -- claimed responsibility for the attack.

"Thanks to God, the so-called Sderot settlement was targeted by a homemade rocket," the Ahfad al-Sahaba group said in a statement.

The same group has claimed responsibility for other recent attacks but Israel holds Hamas responsible for all such rocket fire.

Shortly afterwards, Hamas security sources said Israeli tank fire struck a post run by its military wing, the Ezzedine Al-Qassam Brigades, east of Beit Hanoun near the border with Israel.

Three air strikes also targeted other bases in the Khan Yunis area in the south of the enclave, the sources said, while two others hit Hamas posts near Gaza City, an AFP journalist reported.

Israel's military did not provide details on its strikes, saying only that it "targeted a number of Hamas posts".

"Today’s attack, the second since the beginning of August in the city of Sderot, is the direct result of Hamas’s terror agenda in the Gaza Strip that encourages deliberate attacks against Israeli civilians," military spokesman Peter Lerner said in a statement.

As Israeli aircraft continued to carry out surveillance in the afternoon, Hamas denounced the strikes, calling them an "escalation" and saying it would not be able to "remain with its arms folded if it continues".

Islamic Jihad, which has a strong presence in Gaza, said "the resistance is not looking for an escalation but it is ready for any option to respond."

- Stronger response -

The Israeli army and Palestinian militants in Gaza have fought three wars since 2008 and there are frequent flare-ups along the border.

Israel often responds to rocket fire from Gaza with air and tank strikes, but recent responses have been stronger than in the past.

That has led some analysts to question whether the change is the result of a new policy by hardline Defence Minister Avigdor Lieberman, who took office in May.

In August, Israel carried out dozens of retaliatory strikes after a rocket hit Sderot, a far larger response than usual.

Israeli media reported that attack was the first time downtown Sderot had been struck by a rocket from Gaza since the last war in 2014.

The 2014 conflict was the most devastating of the three, killing 2,251 Palestinians and leaving 100,000 homeless.

Seventy-three Israelis, most of them soldiers, died in the conflict.

A delegation from the International Criminal Court is visiting Israel and the Palestinian territories this week, its chief prosecutor said Wednesday, against the backdrop of a probe into the last Gaza war.

Gaza has been under an Israeli blockade for nearly a decade, with Israel seeking to prevent the entry of material it believes could be used for military purposes.

UN officials have called for the blockade to be lifted, saying conditions are deteriorating in the impoverished enclave of 1.9 million people.

Source: AFP