The United States said on Friday that it regrets the loss of "innocent" Palestinian lives during Israel's military offensive but defended Israel's military action as fighting against "terrorists."

"It is a true tragedy that innocent life has been lost, nobody can replace those people," State Department spokesman Sean McCormack said at a briefing.

McCormack made the remarks after several fresh and successive Israeli airstrikes killed nine Palestinians on Friday evening in northern and southern Gaza Strip, and the death toll of the still ongoing Israeli operations hit to 37 Palestinians killed in recent three days.

"But let us remember, the situation originally developed because you have people -- terrorists -- continuing to launch rockets into Israel. Israel has taken steps to defend itself," McCormack said.

McCormack also stopped short of making an appeal for restraint from the Israeli side.

U.N. Secretary-General Kofi Annan has expressed deep concern about the continuing escalation of violence and rising death toll caused by Israel's military action in recent days.

Source: Xinhua