Both Israel and Hamas vowed to stop fighting two weeks ago, but since then attacks have continued. Before his country launched airstrikes on Sunday, Israeli Prime Minister Ehud Olmert had warned Hamas of a “disproportionate Israeli response” to Hamas rocket and mortar attacks.
Palestinian President Mahmoud Abbas, meanwhile, is headed to Cairo, though his influence is surely weakened by the recent fighting.
Israeli aircraft have bombed a Hamas security target in Gaza City and tunnels used by the militant group along the border with Egypt.
There were no reports of casualties after the strikes late on Sunday.
Israeli PM Ehud Olmert earlier vowed a “disproportionate” response to rocket attacks on Israel from Gaza.
He was speaking soon after at least two rockets hit southern Israel. Later three Israelis were injured in a mortar barrage by Palestinian militants.