Israel Air Force aircraft on Monday morning struck Palestinian militants in the northern Gaza Strip as they were preparing to fire rockets at southern Israel, the army said in a statement.

The attack also came in response to mortar shells fired at soldiers on a routine patrol along the border fence, the army said.

Palestinian medical officials said four civilians were injured in the strike, and evacuated to a hospital in the vicinity, the Palestinian news agency Ma'an reported.

Earlier on Monday, four rockets fired from Gaza exploded in open areas in the western Negev, causing no injuries or damage.

A new round of cross-border hostilities flared up two weeks ago, following an Israeli airstrike that killed a Palestinian militant in southern Gaza.

Last week, militants in the coastal enclave fired dozens of rockets into Israel, while Israeli airstrikes killed five militants.