Palestinian President Mahmoud Abbas cut short his trip to Europe to return to the West Bank amid Israeli strikes on the Gaza Strip and which left more than 13 people killed and about hundred others injured, PLO official Saeb Erekat said Thursday. Abbas has asked the Palestinian envoy to the UN to galvanize Arab states in order to halt the violence, which has killed 15 Palestinians and three Israelis in 24 hours. President Abbas has sent a letter to the president of the UN Security Council current session (India) through palestine’s permanent delegate to the UN ambassador Riyad Mansour asking for urgent action and halt the israeli aggression on the Gaza strip, Erekat added. The Security Council met briefly on Wednesday, but did not take any action. Abbas meantime pressed for an emergency Arab League session. The regional body is set to meet Saturday over the latest fighting, sparked by Israel’s assassination of a top Hamas military leader in Gaza on Wednesday. “We have a very grave situation in Gaza, we have situation deteriorating on the hour every hour and President Abbas now is in touch with Egyptian President Mohamed Morsi , Arab League Secretary General Dr. Nabil al-Arabi the UN Chief Ban Ki-moon and others in Europe and the United States, hoping to begin a process of de-escalation of the conflict,” Erekat told reporters in the Swiss capital Berne, where Abbas met Swiss Foreign Minister Didier Burkhalter.