A day after a volley of rockets broke a tense calm on the border with Lebanon, Israel’s ambassador to the United Nations called on the organization to act in southern Lebanon and prevent further border incidents.

In a missive sent to Secretary General Ban Ki-moon Monday, Ron Prosor said the Security Council should work to assure the rocket fire does not evolve into a wider conflict.

“I urge the Security Council to address the escalation on the part of Lebanon before the situation further escalates,” he wrote. “Israel has shown maximum restraint, but will continue to exercise its right to self-defense, as appropriate, and take all necessary measures to protect its citizens.”

On Sunday, four rockets were fired at Israel from southern Lebanon, with two landing in open areas near the town of Kiryat Shmona. The missiles landed in open areas and caused no damage, but shocked the country after several years of relative calm along the northern front.

Prime Minister Benjamin Netanyahu said he would hold Beirut and the terror group Hezbollah responsible, though some analysts said the rockets may have been the work of other militiamen.

“Israel cannot be expected to stand by as its citizens become the victims of persistent attacks,” Prosor wrote. “The reign of terror is the result of a complete drought in leadership on the part of the Lebanese government, which is harboring Hezbollah terrorists and undermining regional stability.”

The rockets were the second violent border incident in several days, after an IDF soldier was killed by sniper fire from a Lebanese soldier last week while driving near the border.

In both cases UNIFIL, which has monitored the border between the countries for the United Nations since the 2006 Second Lebanon War, convened officials from both sides in a bid to calm tensions.

Maj. Gen. Paolo Serra made contact with the Israeli and Lebanese armies immediately after Sunday’s incident and urged both sides to exercise “maximum restraint.” He said UNIFIL had stepped up patrols in southern Lebanon to prevent any further incidents.

“I have been assured by the parties of their full cooperation with UNIFIL in this effort and of their continued commitment to the cessation of hostilities,” Serra said in a statement. “It is of paramount importance to identify and apprehend the perpetrators of this attack and we will spare no efforts to this end working in cooperation with the Lebanese Armed Forces.”

Prosor made it clear that, regardless of who was behind the incidents, it is the Beirut authorities that must bear the blame.

“The Government of Israel holds the Lebanese government responsible for the escalation of violence in recent weeks,” Prosor wrote. “In addition to the wave of rockets, armed fighters have been firing across the Blue Line into northern Israel throughout the month of December. And just last week, a member of the Lebanese Armed Forces shot and killed an Israeli, Shlomi Cohen, while he was driving in a civilian vehicle inside Israel.”

The ambassador highlighted Hezbollah’s presence in Lebanon and noted that its military use of the area near the border with Israel is a war crime.

“In direct violation of international law, Hezbollah has stationed tens of thousands of missiles and rockets in the heart of Southern Lebanon’s civilian population,” he wrote. “Hezbollah is committing a double war crime; first by using Lebanese civilians as human shields and second by targeting Israeli citizens.”