GAZA  At least four Palestinian militants were killed in an Israeli airstrike in central Gaza late Saturday as they were preparing to fire a crude, locally-produced rocket into Israel, Palestinian security officials said.

Acknowledging the strike, the Israeli military said in a statement that more than 200 rockets and mortar shells had been fired at Israeli territory since the beginning of 2010.

Israeli security officials have noted an increase in the rate of rocket fire out of Gaza in the past three months. Although these attacks seem to be the work of organizations other than Hamas, the Islamic militant group that controls Gaza, Israel says it holds Hamas responsible for all fire emanating out of the Palestinian coastal enclave.

Security officials in Gaza said that the rocket that the militants were carrying had not exploded and that pieces of an Israeli missile were found at the scene.