Israeli forces have fired on groups of protesters at borders with the Palestinian territories, Syria and Lebanon.

以色列军队在与巴勒斯坦、叙利亚和黎巴嫩边境交界处向成群的抗议者开枪射击。

Reports say that at least 12 people have died and dozens more have been injured.

In one incident, thousands of Palestinian supporters from Syria entered the Golan Heights, Israel says.

Palestinians are marking the Nakba or Catastrophe¹, their term for the founding of the Israeli state in 1948.

Hundreds of thousands of Palestinians fled or were forced out of their homes in fighting after its creation.

Responding in a televised address to Sunday's violence, Israeli Prime Minister Benjamin Netanyahu said he hoped "calm and quiet will quickly return, but let nobody be mistaken, we are determined² to defend our borders and sovereignty（主权，君主） ".

Later on Sunday, security forces in the Egyptian capital Cairo fired warning shots and tear gas to break up protests outside the Israeli embassy.

UN Secretary General Ban Ki-moon has called for calm and urged all sides to show "utmost responsibility".

In a statement, he said there was an "unsustainable（无法支撑的） status quo in the Arab-Israeli conflict, which is only thrown into sharper relief by the profound political changes now under way in the region" and called for a renewed effort to reach comprehensive peace in the region.