The distinctive whoosh of a longer-range rocket leaving Gaza set sirens wailing in Tel Aviv or Jerusalem within minutes, as Hamas militants broke new ground in the fight against Israel.

And although the Islamists' firepower was hard hit during its eight-day confrontation with Israel, Hamas has valuable technical knowledge at its fingertips which could be used to rebuild its arsenal.

In the first hours of Israel's bombardment of the Hamas-run Gaza Strip, officials said the air force had destroyed the lion's share of the enclave's arsenal of rockets with a range longer than 40 kilometres (25 miles).

"The army took out most of the rockets aimed at central Israel and thousands that were aimed at southern Israel," Prime Minister Benjamin Netanyahu told pilots who took part in Gaza sorties on Sunday.

"Once the campaign achieved its goals, there was no reason to continue it," he said in remarks relayed by his office.

But Hamas and Islamic Jihad still managed to fire five rockets at the Tel Aviv area, three of which were intercepted by the Iron Dome defence system, with another two landing in the Mediterranean Sea. Another rocket hit a block of flats in Rishon Letzion, south of Tel Aviv, causing extensive damage.

Four more rockets struck outside Jerusalem.

The strikes marked the longest distances ever reached by rockets fired by militants in Gaza.

Ever since the 1991 Gulf War when Saddam Hussein's Iraq fired 39 Scud missiles at Tel Aviv, the Palestinians have been waiting to see who would "launch missile number 40," said Mukhaimer Abu Saada, professor of political science at Gaza's Al-Azhar University.

Even during a 2006 war between Israel and Lebanon's Hezbollah, the Shiite militia warned it would "strike beyond beyond Haifa... but it never targeted Tel Aviv," he said.

"To be able to make the enemy -- the Israelis -- suffer, looking for shelter and screaming: that is the taste of victory for the Palestinians."

The big question, analysts say, is how many rockets are left in Gaza beyond the initial 10,000 believed to have existed before the confrontation, and how quickly Hamas is able to rebuild its arsenal.

During the operation, the Israeli military said it struck more than 1,500 targets, including 19 militant command centres, 26 weapons manufacturing and storage facilities and hundreds of underground rocket launchers.

-- Locally-produced rockets --

In announcing his acceptance of the Egyptian-brokered truce deal on Wednesday, Netanyahu said Israel and the United States had agreed to work together to prevent the smuggling of weapons to Gaza militants, "most of which comes from Iran."

According to a report published the same day in Israel's left-leaning Haaretz daily, Iran has over the past two years smuggled a number of Fajr 5 rockets with a range of up to 75 kilometres (47 miles) into Gaza via Sudan and Egypt.

"At the same time, Hamas and Islamic Jihad manufactured 200mm diameter rockets -- whose range is close to 80 kilometres (50 miles) -- in the strip, using know-how provided by Iran," wrote the paper's defence correspondent, Amos Harel.

"Until now, roughly 10 medium-range rockets have been fired toward the Tel Aviv area and the Jerusalem region. Most of these have been the improvised 200mm rockets produced locally in Gaza. Israeli intelligence believes that only a small number of these medium-range rockets remain," he wrote.

Iran's Revolutionary Guards chief General Mohammad Ali Jafari said the same day that Tehran had not supplied Fajr 5 missiles to Gaza, rather had shared the "technology," meaning that such missiles could be "rapidly produced" in the territory.

During the confrontation, militants from Hamas's armed wing, the Ezzedine al-Qassam Brigades, said they had fired 1,573 rockets at southern Israel, including one called the M75 -- a "locally-made" rocket with a range of at least 75 kilometres.

"Not all the longer-range missiles were smuggled into Gaza. The missiles that struck Gush Etzion (south of Jerusalem) -- the M75s -- are not Iranian missiles," Abu Saada said. "This is a Hamas-made missile."

"Even if Egypt (is) able to control the tunnels, (to) close them down, Hamas will be able to manufacture its own," he said, pointing out that Hamas was managing to smuggle both parts and weapons into Gaza even before Israel withdrew all of its soldiers and settlers in 2005.