A barrage of rockets from Gaza hit Israel during the night, the army said Saturday, hours after five Palestinians were killed during clashes on the Israeli border, in a flareup that could jeopardise truce efforts.

The largest projectile attacks in months and the border fatalities came despite talk of progress towards an Egyptian-brokered deal to end months of often violent protests along the border.

"Overnight, dozens of rockets were launched from the Gaza Strip at communities in southern Israel," the army said in a statement, putting the exact number in a separate announcement at 30.

"The IDF's Iron Dome aerial defense system intercepted approximately 10 projectiles," the army said, adding that two rockets fell within the Gaza Strip while the others landed in "open areas".

Israeli medics said seven civilians were being treated for shock.

In response to the rockets, Israeli fighter jets, helicopters and drones struck "approximately 80 Hamas targets throughout the Gaza Strip".

There were no reports of Gaza casualties as a result of the strikes.

Hamas, the militant Islamist rulers of Gaza, did not claim responsibility for the rockets, but Israel holds it responsible for any launches from the coastal enclave.

"The rocket fire is conducted in a terror-filled atmosphere which is generated by Hamas in the area of the security fence and in acts such as tonight's events," the army said.

Islamic Jihad, the second largest militant group in Gaza, hailed the rocket fire in a statement as a response to "Israeli aggressions", stopping short however of directly claiming responsibility for the launches.

A Hamas official said that following the escalation Egypt was again seeking to negotiate a return to calm.

- 'Riot dispersal means' -

Earlier, five Palestinians aged between 22 and 27 died in separate incidents along the border fence, the Gaza health ministry said.

The army did not comment on the deaths but said around 16,000 "rioters and demonstrators" had gathered along the border, with some setting tyres alight and hurling rocks, firebombs and grenades towards soldiers.

Troops responded with "riot dispersal means", a spokesman added.

Three of the men were shot dead east of Khan Yunis in southern Gaza, while one was killed east of Jabalia in the north of the coastal territory, the health ministry said.

A fifth man died east of Bureij in central Gaza when a hand grenade he was holding exploded accidentally, witnesses said.

Palestinians have gathered for protests along the Gaza Strip's border at least weekly since March 30.

At least 212 Palestinians have been killed by Israeli fire in Gaza since the protests began, according to figures collated by AFP.

The majority have died during protests, while smaller numbers have been killed by airstrikes and tank fire.

One Israeli soldier was shot dead by a Palestinian sniper along the border in the same period.

The protesters are calling to be allowed to return to lands their families fled or were expelled from in a 1948 war surrounding the creation of Israel and which are now inside the Jewish state.

They are also protesting over Israel's crippling blockade of Gaza.

Israel accuses Hamas of orchestrating the often violent demonstrations.

Israel and Hamas have fought three wars since 2008 and much of the international community considers the Islamist movement a terrorist organisation.

- Truce deal at risk -

The fresh violence could also scupper hopes of a deal to end the months of protests.

Egypt and the United Nations have been brokering indirect negotiations between Hamas and Israel with the aim of calming the situation amid fears of another war.

Last week, a rocket fired from Gaza hit an Israeli home, narrowly avoiding killing a family. In response the Israeli army carried out air strikes on around 20 Hamas targets in Gaza.

The London-based Arabic newspaper Al-Hayat reported Friday that a deal had been reached that would see the protests end in exchange for an easing of Israel's blockade.

Hamas officials denied a deal had been struck but confirmed to AFP that progress was being made.

"We expect to reach an agreement very soon," a senior Hamas official said earlier Friday on condition of anonymity.

Israel also fully reopened its border crossings with the Gaza Strip this week following a week of relative calm.

It allowed dozens of trucks of fuel paid for by Qatar into the strip, having previously banned their entry in response to the border violence.

Israel says the decade-long blockade is necessary to isolate Hamas, while critics say it amounts to collective punishment of Gaza's two million residents.