The health ministry in Gaza says two teenagers have been killed and ten others injured in an airstrike in Gaza City.

Witnesses say Israeli warplanes dropped four bombs Saturday afternoon on an unfinished building near a Hamas police and security compound, reducing the old structure to rubble. The four-story building is adjacent to a public park.

It marks the first casualties in the dramatic flare-up in violence between Israel and Hamas.

Striking in the heart of Gaza City is typically only seen during full-blown conflicts like the war of 2014 and could mark a sign that violence is escalating.

The Israeli military carried out its largest daytime airstrike campaign in Gaza since the 2014 war on Saturday as Hamas reportedly fired rockets into Israel.