GAZA CITY, Gaza Strip (AP) — Israeli aircraft struck the Gaza Strip on Sunday, killing a Palestinian man, as militants bombarded the Jewish state with rockets and mortars in a fierce second day of fighting.

The clashes have threatened to draw the two sides into a major confrontation two months before Israeli elections, a possibility underlined by Prime Minister Benjamin Netanyahu's warning that Israel was ready to strike harder against the militants if the violence persisted.

"The world must understand that Israel will not sit idly in the face of attempts to attack us. We are prepared to intensify the response."

While cross-border fighting is a common occurrence, hostilities spiraled sharply over the weekend. An explosives-packed tunnel under the Gaza-Israel frontier blew up Thursday night in what the Israeli military called an attempt by Palestinian militants to kill or kidnap soldiers.

That set off a cycle of violence including Israeli airstrikes that have killed six Gazans and wounded almost 40, rocket and mortar barrages that have wounded four Israeli civilians, and the firing of an antitank missile into an Israeli military jeep patrolling the frontier area. The missile attack left four wounded, one critically — rare casualties for the Israeli side.

With the rocket fire disrupting life for tens of thousands of Israelis and soldiers being attacked with increasingly sophisticated weapons, the Israeli government is under stiff pressure from citizens to put an end to the violence.