U.S. 'Deeply Concerned' by Israel-Gaza Violence

The United States expressed concern Saturday over deadly violence between Israel and Palestinians across the Gaza border and urged both sides to restore calm.

"We are deeply concerned by the renewal of violence in southern Israel," said State Department spokeswoman Victoria Nuland in a statement. "We call on both sides to make every effort to restore calm."

Israeli air strikes on Gaza since Friday have killed 15 Palestinians, including a top militant, medics, with militants firing 100 rockets into the Jewish state.

It was the deadliest unrest between Israel and the Palestinians across the Gaza border in more than three years.

"We condemn in the strongest terms the rocket fire from Gaza by terrorists into southern Israel in recent days, which has dramatically and dangerously escalated in the past day," Nuland said.

"We call on those responsible to take immediate action to stop these cowardly acts."

Palestinian militants, however, have vowed to avenge their dead and Israel has threatened to hit back if its citizens come under renewed rocket attacks from the coastal enclave.