The Israeli military has resumed strikes on targets "across Gaza" in response to rocket fire from the territory.

The new round of fighting came after a three-day truce expired this morning and Israel-Hamas talks that have been under way in Cairo on a new border deal for blockaded Gaza reached deadlock.

After the end of the temporary 72-hour ceasefire, Gaza militants fired at least 17 rockets at Israel.

Gaza's police said Israel then resumed tank fire and launched an air strike that hit a farm south of Gaza City.

The Israeli military said that following renewed rocket fire, it targeted sites linked to militant groups "across Gaza".

It was not clear if the renewed fighting would derail the Cairo talks aimed at reaching a sustainable truce, or whether the Egyptian mediators can find a way to prevent a further escalation and a return to full-out war.

Militants from Gaza fired first, after the temporary truce expired at 6am UK time, launching rockets toward Israel. Most landed in open fields, but two were intercepted over the coastal city of Ashkelon.

Gaza police said an Israeli air strike hit in the area of a housing estate in northern Gaza and there were reports of casualties.

Police also reported fire from Israeli tanks on northern Gaza and from Israeli gunboats at the central area of the territory.

In Cairo, both sides are under intense international pressure to reach a deal. As part of such an arrangement, Israel wants to see Hamas disarmed or prevented from re-arming, while Hamas demands Gaza's borders be opened.

No progress was reported in all-night talks that ended before dawn.

Sami Abu Zuhri, a Hamas spokesman in Gaza, said that while his group did not agree to an extension of the truce, it was willing to continue the talks.

Hamas, which has seen its popularity boosted for confronting Israel, entered the Cairo talks from a point of military weakness after losing hundreds of fighters, two-thirds of its rockets arsenal and all of its attack tunnels.

With no definitive statement that it would return to open war, the group appeared to be keeping its options open while several smaller Gaza militant organisations claimed responsibility for today's rocket fire.

The Israeli delegation left Cairo earlier.

Israeli government spokesman Mark Regev would not say whether Israel is interested in extending the ceasefire or if it will respond to the rockets.

Mr Regev blamed Gaza militants for breaking the ceasefire.

"The ceasefire is over," he said. "They did that."