Israeli aircraft struck a number of sites in the Gaza Strip from the air early on Wednesday, residents and the Israeli military said, after a rocket that Palestinian militants fired from the enclave landed near the Israeli port city of Ashdod.

The Israeli military said it struck four "terror infrastructures" in the southern Gaza Strip and that hits were confirmed. There were no reports of any casualties or damage.

Gaza residents said missiles struck several locations throughout the Gaza Strip, including places used as training camps by Islamic Jihad militants on sites that had been Israeli settlements before Israel withdrew from Gaza in 2005.

Tuesday's rocket landed near Ashdod some 20 kilometres (12 miles) north of the Gaza border and security forces were searching for remnants. It was the longest-range militant rocket strike since a truce that ended the 50-day war last year.

There was no immediate claim of responsibility in Gaza for the rocket launching.

"These strikes are a direct response to Hamas and the aggression against Israeli civilians originating from the Gaza Strip," military spokesman Lieutenant-Coloner Peter Lerner said in a statement. "The reality that Hamas' territory is used as a staging ground to attack Israel is unacceptable and intolerable and will bear consequences."

Last year, militants in Gaza launched thousands of rockets and mortar bombs into Israel during a July-August war in which Israeli shelling and air strikes battered the small, coastal Palestinian enclave.

The region has been largely quiet since the August ceasefire.

Israeli media speculated that infighting among Islamic Jihad militants in Gaza Strip may have precipitated the rocket firing without the permission of Gaza's Islamist Hamas rulers.

Rival militant factions in Gaza are angry that months after the end of the war, no progress has been made to improve the isolated enclave's plight and pledges for funding to reconstruct buildings devastated during the war have not been honoured.

Reconciliation efforts between Hamas and the Western-backed Palestinian Authority led by President Mahmoud Abbas have faltered, adding to hardships and hampering foreign aid donations and the import of building materials.

Israel maintains a partial blockade on the territory and Egypt largely keeps the Rafah border crossing closed. Hamas has imposed a "solidarity tax" and salaries for workers not aligned with the Palestinian Authority are not being paid in full. – Reuters