A child was killed and 30 people wounded in an Israeli air strike on a refugee camp in Gaza City on Monday just minutes into an Israeli-declared truce, medics said.

The strike hit a house in the beachfront Shati refugee camp, killing an eight-year-old girl, emergency services spokesman Ashraf al-Qudra told AFP.

Witnesses and several AFP correspondents reported hearing the whistle of a missile fired from an F16 warplane before it crashed into a house wedged between two tall buildings inside the camp.

An AFP correspondent said the strike hit at 0706 GMT - ie six minutes into the lull.

The Israeli army said it was looking into the incident, but gave no further comment.

With only a narrow alley leading to the house, it was not possible to get rescue equipment to the scene, with a long line of people passing out chunks of rubble by hand, an AFP correspondent said.

The strike cause the house to pancake, leaving only a very narrow gap for rescuers to get inside, some of whom were bloodying themselves in the effort, he said.

From within, they managed to pull the body of a young girl wearing pyjamas whose spine appeared to be broken in several places, with rescuers struggling to get her onto a stretcher, he said.

Earlier on Monday, the Israeli army announced a unilateral seven-hour lull, to begin at 0700 GMT.

Hamas said it would not be observing the truce, and warned people to exercise extreme caution when venturing out onto the streets after earlier temporary ceasefire arrangements collapsed into a frenzy of bloodshed.