CAIRO, Egypt -- An Egyptian effort to broker an end to a monthlong war between Israel and Hamas militants in the Gaza Strip appeared to collapse Tuesday after Israel walked out on the talks in response to a barrage of Palestinian rocket fire.

The Israeli walkout occurred just hours before a midnight deadline, leaving the fate of the negotiations in question and raising the possibility of a resumption of heavy fighting.

The fighting appeared to pick up late Wednesday. The Israeli military said a total of 10 rockets had fallen, including one that damaged a coffee shop in southern Israel.

Palestinian officials in Gaza reported more than two dozen Israeli airstrikes. At least 21 people, including 14 women and children, were wounded in a strike that hit a building housing the offices of Hamas' Al Aqsa TV station in Gaza City.

Israel's civil defence authority, the Home Front Command, ordered authorities to reopen public bomb shelters within a 40-kilometre range of Gaza.

"The Cairo talks were based on an agreed premise of a total cessation of hostilities," Israeli government spokesman Mark Regev said. "When Hamas breaks the cease-fire, they also break the premise for the Cairo talks. Accordingly, the Israeli team has been called back as a result of today's rocket fire."

He would not say whether the team would return to Cairo, or whether Israel would resume cease-fire talks.

Egyptian security officials said Egypt was still pressing the two sides to agree on a cease-fire. The officials spoke on condition of anonymity because they were not authorized to speak to the press.

The breakdown dealt a tough blow to nearly a week of Egyptian-led diplomacy meant to end the heaviest fighting between Israel and Hamas since the Islamic militant group seized control of Gaza in 2007. More than 2,000 Palestinians, most of them civilians, were killed, according to Palestinian and UN officials, and tens of thousands of people are homeless. Israel has claimed the number of militants killed was much higher, and it blames Hamas for causing civilian casualties by staging attacks from residential areas. Sixty-four Israeli soldiers, two Israeli civilians and a guest worker have also been killed.

Hamas is seeking an end to a seven-year Israeli-Egyptian blockade that has ravaged Gaza's economy, while Israel wants guarantees that Hamas will disarm.

In nearly a week of indirect talks, Egypt appears to have made little headway in resolving the differences. Late Monday, it secured a 24-hour extension to a temporary truce to allow more time for a last-ditch attempt to reach a longer-term deal.

An Egyptian compromise proposal calls for easing the blockade, but not lifting it altogether and opening the territory's air and seaports as Hamas has demanded.

While the plan does not require Hamas to give up its weapons, it would give Western-backed President Mahmoud Abbas, whose forces were ousted by Hamas in 2007, a foothold back in Gaza running border crossings and overseeing internationally-backed reconstruction. Abbas' presence would minimize friction with Israel and allow large amounts of international aid to flow into Gaza for reconstruction.

In Cairo, members of the Palestinian delegation, which is comprised of various factions, said no progress had been made in Tuesday's talks.

"Israel insisted during the talks on disarming the factions in Gaza, and that created huge difficulties during the talks," said Kais Abdelkarim, a Palestinian negotiator.

The chief Palestinian negotiator, Azzam al-Ahmad, said the Palestinians had submitted a final proposal in hopes of reaching a breakthrough.

"We gave the Egyptians our final position. We are waiting for them to come back with a response," he said.

But Hamas' chief negotiator, Izzat Risheq, was pessimistic.

"Egyptian mediators are waiting for an answer from the enemy delegation to the response of the Palestinian delegation," he wrote on Twitter. "Even at 12 o'clock, the end of the deadline for the truce ... I do not think there will be an answer."

Hamas finds itself pressured by both Egypt and the Palestinian Authority to accept a less than perfect deal with Israel, but needs to show the people of Gaza that the enormous sacrifices they endured in the fighting were not in vain.

In an apparent attempt to pressure Hamas, Egypt said early Monday it would co-host an international fundraising conference for Gaza -- but only if a deal is reached first.

That appears to play into the hands of the Abbas' Palestinian Authority, which is eager to regain control of Gaza.

The disagreements have focused around the lifting of the blockade.

A member of the Palestinian delegation said that Israel was offering to ease the blockade by opening border crossings to some goods and people, but was insisting that it retain the right to limit the imports of material like cement, and chemical and metal products, which Israel says can be used for weapons manufacturing.

Hamas fears the arrangement would allow Israel to retain the right to close the crossings whenever it wished and is pushing for more Palestinian input into such decisions.

The Palestinians are also seeking assurances that Israel will discuss the reopening of the seaport and airport, and the release of Palestinian prisoners held in Israeli jails, a month after a formal cease-fire takes hold. The Israelis want at least three months of quiet, Palestinians say.

Palestinian delegates say that Israel has agreed to extend the maritime territory in which Gaza fisherman can venture out from five to 10 kilometres and eventually to 20 kilometres from the shore, but that it was standing firm against Hamas' demand for unsupervised exports from the strip.

The Gaza blockade, imposed after Hamas seized control of the territory in 2007, has greatly limited the movement of Palestinians in and out of the territory of 1.8 million people, restricted the flow of goods into Gaza and blocked virtually all exports.

Israel says the blockade is needed to prevent arms smuggling, but critics say the measures have amounted to collective punishment.

The latest round of Gaza fighting was precipitated by massive Israeli arrests of Hamas members in the West Bank in the aftermath of the abduction and killing of three Israeli teenagers in June. Their deaths were followed by the slaying of a Palestinian youth in Jerusalem in what was a likely revenge attack.

Associated Press writers Maggie Michael in Cairo and Ibrahim Barzak in Gaza City, Gaza Strip, contributed to this report.