Israel says could get tougher on Gaza after warplanes hit Hamas

Prime Minister Benjamin Netanyahu said Israel could step up its "intensity" on Gaza, after a new flare-up that saw Israel carrying out air strikes and Palestinians launching rockets and mortar shells.

The latest spike in tensions follows weeks of deadly protests and clashes along the Gaza-Israel border as well as the worst military escalation last month since a 2014 war.

It comes as US President Donald Trump's special envoy Jason Greenblatt and adviser Jared Kushner visit the region to discuss issues including the Palestinian-Israeli peace process.

Israeli planes initially targeted three Hamas military positions overnight in Gaza in response to kites and balloons carrying incendiary and explosive devices launched into Israel from the Palestinian territory, the army said.

"Hamas and other terrorists, but mainly Hamas" hit back after the first air raids with more than 45 rockets and mortar rounds fired from Gaza towards Israel, seven of which were intercepted by the Iron Dome missile defence system, Israeli military spokesman Jonathan Conricus said.

Three more landed inside the Jewish state, he said, but did not account for the remainder.

In response, Israeli planes carried out more raids against 25 "terror objectives" including an underground training compound, according to the army.

Medical sources in Gaza, which is controlled by Hamas, said five people were lightly injured in the strikes.

Speaking about Israel's plans regarding Gaza, Netanyahu said he would not go into detail, pledging however that "the intensity will be stepped up as necessary".

"We are prepared for any scenario and our enemies would do well to understand this," he said at a military ceremony in southern Israel.