Hamas officials said Friday an agreement with Israel on a long-term cease-fire in Gaza could be announced within days, but a new cycle of attacks by both sides strained a temporary truce.

Two rockets and a mortar shell fell fired from Gaza hit southern Israel, the Israeli military said. No one was injured, and no Palestinian group took responsibility for the attacks.

Hours later, Israel retaliated with an airstrike that killed a man and critically wounded another near the Gaza town of Khan Younis, Palestinian security officials said. The dead man was a member of the small, violent Popular Resistance Committees group.

The Israeli military, confirming the strike, said the men were planning an attack on Israel.

The Khan Younis strike was followed by air attacks on what the military said were six weapons-smuggling tunnels under the Gaza-Egypt border. The military said "secondary explosions" were observed at some of the sites, a phrase used to indicate that arms or explosives were stored there. A spokesman said the strikes were in response to the earlier Palestinian attacks.

There were no reports of Palestinian casualties in raids on the tunnels.

Rocket fire and shooting incidents along the Gaza-Israel border have persisted since the end of Israel's devastating offensive against Hamas in the territory. Israel halted the operation on Jan. 18, and Hamas declared a cease-fire later the same day.

Friday's exchanges came as Hamas officials said talks in Cairo on a long-term truce were close to success.

A Hamas delegation is in the Egyptian capital, and an Israeli envoy has been flying in periodically from Tel Aviv. Egypt is mediating between the two sides because they will not talk directly to each other.

Taher Nunu, a Hamas spokesman in Cairo with the group's truce delegation, said Friday he expects an agreement "within the coming three days." He said progress had been made on a cease-fire, on a reconciliation between Hamas and Fatah, and on reconstruction funds for Gaza.

"Many obstacles have been resolved, especially stopping all forms of aggression and the issue of the quality and kind of goods (entering Gaza) and the opening of the border," Nunu said in a statement e-mailed to reporters in Gaza.

The border crossings have been blockaded by Israel and Egypt since Hamas violently seized power in the territory in 2007, defeating the rival Fatah faction.

Late Thursday, Hamas deputy leader Moussa Abu Marzouk told Egypt's official MENA news agency that the Islamic militant group has agreed to an 18-month truce with Israel, and that it would be announced within two days after the group consults with other Palestinian factions.

Abu Marzouk said the deal calls for Israel to reopen its border crossings into Gaza, fulfilling Hamas' central demand.

Egyptian state-run newspapers Friday quoted Egypt's top mediator, intelligence chief Omar Suleiman, as saying that four obstacles remained to be resolved; firing rockets, establishing a buffer zone between Gaza and Israel, a Hamas commitment to respect calm and a halt to weapons smuggling into Gaza.

Israeli defense officials said the talks were serious and making progress. An initial agreement could involve a partial opening of Gaza's crossings, they said, with a later agreement to include the release of Sgt. Gilad Schalit, an Israeli soldier held by Hamas since 2006, in return for the release of Palestinian prisoners demanded by Hamas.

Talks on Schalit's release have stalled over disagreements about which prisoners Israel would free. The hundreds of names on Hamas' list include senior militants and masterminds of deadly suicide bombings.

The officials spoke on condition of anonymity because the details remain classified.

It was unclear whether the results of Israel's national election this week would affect the Cairo talks. The election ended with the moderate foreign minister, Tzipi Livni, winning one more parliament seat than hard-line Likud leader Benjamin Netanyahu.

But with hawks now forming a majority in the incoming parliament, Netanyahu has better chances of cobbling together a coalition government. He met with potential allies Friday. Coalition wrangling is expected to last weeks, at least.

A new government is likely to be either a hard-line coalition led by Netanyahu or a centrist coalition involving a power-sharing arrangement between Netanyahu and Livni.

Violence also erupted Friday in the West Bank city of Hebron. Staff at a local hospital said a teenage boy was killed by Israeli army fire during a clash between troops and stone-throwing Palestinian youths.

Doctors at Alia hospital named the dead boy as Izzadine Jamal, 14. They did not know if he was among those attacking the Israelis.

The army said dozens of Palestinians hurled rocks at a military guard tower next to an Israeli settlement and a soldier shot the ringleader.

Hebron, the largest city in the West Bank, is divided between Israeli and Palestinian zones of control and clashes are frequent. About 500 Jewish settlers live there among about 170,000 Palestinians.