Palestinian President Mahmoud Abbas ordered Friday evening a three-day official mourning, with Palestinian flags at half-mast in occupied territories, for 15 Palestinians killed in Israeli attacks on the Gaza Strip in last 24 hours.

Speaking to reporters in the West Bank city of Ramallah, Abbas condemned Israeli military escalation as massacre against the Palestinian people.

"What happened in Gaza is a massacre against humankind. Israel carries out the unjustified and deadliest crimes and extermination against our people," Abbas said.

"I don't know the reasons which encourage the Israeli government to commit such horrible crimes."

Abbas appealed to the international community, the UN Security Council and the Middle East Quartet to intervene immediately to " put an end to the Israeli aggression against our people".

Eight innocent civilians including women and children were killed and 35 others wounded at the beach of the northern Gaza town of Beit Lahia on Friday when they came under Israeli bombing.

Three suspected Palestinian militants were killed in four Israeli airstrikes on the northern Gaza Strip on Friday.

On Thursday night, four Palestinians were killed in southern Gaza Strip, including the Popular Resistance Committees leader Jamal Abu Samhadana, in an Israeli airstrike on a training camp that belongs to the militant group.

Source: Xinhua