A senior Islamic Hamas movement's official announced that a new understanding on restoring calm in Gaza with Israel had been reached on Saturday night based on the principle of "calm for calm."

Ayman Taha, a senior Hamas leader, told Xinhua that extensive efforts were exerted by Egypt to restore calm in Gaza and Hamas will stop rocket fire if Israel ends raids.

"Hamas will be watching the situation on the ground within the coming hours and also the seriousness of the Israeli enemy to calm, " said Taha.

Four Palestinians were killed, including a 4-year-old boy, in Israeli airstrikes on Friday and Saturday since al-Qassam Brigades, a Hamas armed wing, announced that it accepted an understanding brokered by Egypt to restore calm in Gaza.

Taha stressed that his movement would never accept unilateral calm "while the Zionist enemy resumes its operations and airstrikes and keeps sending its warplanes to hover over the Gaza Strip round the clock."

Earlier on Saturday, al-Qassam Brigades threatened in a leaflet emailed to reporters to respond to the intensive Israeli aerial assaults and the destruction of security compounds in the Gaza Strip.

Since Monday morning, 15 Palestinians were killed and more than 70 wounded in a wave of violence between Gaza militants and the Israeli army, according to officials in the Hamas-run ministry of health.