GAZA CITY, Gaza Strip — Israel escalated its military campaign against Hamas today, striking symbols of the group’s control in Gaza and firing tank shells that shut down the strip’s only power plant in the heaviest bombardment in the fighting so far.

Flares turned the sky over Gaza City orange overnight and by daybreak, as the conflict entered its fourth week, heavy clouds of dust hovered over the territory. A thick column of black smoke rose from a burning fuel tank at the power plant.

The pounding came after Israeli Prime Minister Benjamin Netanyahu on Monday warned of a “prolonged” campaign against Hamas. It was not clear if this meant Israel has decided to go beyond the initial objectives of decimating Hamas’ ability to fire rockets and demolishing the group’s military tunnels under the Gaza-Israel border.

Already, the intensity and the scope of the current Gaza operation is on par with an invasion five years ago, which ended with a unilateral Israeli withdrawal after hitting Hamas hard.

Israeli warplanes today carried out dozens of attacks, leveling the home of the top Hamas leader in Gaza, Ismail Haniyeh, and damaging the offices of the movement’s Al-Aqsa satellite TV station, a central mosque in Gaza City and government offices.

Haniyeh said in a statement that “destroying stones will not break our determination.”

No one was hurt in Haniyeh’s home.