The Israeli army has warned Palestinians in the northern Gaza Strip to "leave their homes for their own safety".

"Tonight we will send messages to northern Gaza residents urging them to leave their homes for their own safety. It's unsafe to be near Hamas," a statement by the military said.

The warning is not the first time that Israel has urged Palestinians to leave their homes, but it comes as the Jewish state intensified air strikes in the wake of a barrage of rockets fired at Tel Aviv.

At least 16 people were killed in the strikes late Saturday, including 15 in the Tuffah neighbourhood of Gaza City, medics said.

The latest deaths brings the death toll since the beginning of the Israeli airstrikes to 136.

Israel began Operation Protective Edge early Tuesday in an attempt to halt cross-border rocket fire by militant groups.

Since then, militants have fired approximately 520 mortar rounds and rockets that struck Israel, while another 140 rockets were intercepted by the Iron Dome missile defence system, an Israeli army statement said late yesterday.

It is the deadliest violence since November 2012, with a growing number of rockets fired at Jerusalem and Tel Aviv and even as far north as Haifa. 

So far, no Israelis have been killed.

Israel has authorised the call-up of 40,000 reservist troops, and threatened a ground operation to stamp out the rocket fire.

Dublin protest

A protest at the Israeli Embassy in Dublin is dispersing after minor scuffles and attempts by some to breach Garda barriers.

Up to 1,000 people marched from the Dáil to the embassy on Pembroke Road in a protest organised by the Irish Palestine Solidarity Campaign and others.

Earlier, an estimated 1500 people marched from O'Connell Street to the Dáil.

A large contingent of marchers then made their way to the Israeli embassy, where gardaí had erected barriers. 

Some protesters tried to get through the barriers but were prevented by gardaí.

There are no reports of arrests.