LONDON - An exchange of fire across the border between unidentified rocket launchers in southern Lebanon and the Israeli army was an ominous development in the Middle East on Thursday, especially with the death toll in Gaza rising and a cease-fire plan in the balance at the United Nations.

But the obviously provocative nature of the attacks, coupled with the lack of evidence as to who was behind the rocket fire, makes the opening of a second front unlikely at this time. Although rocket fire from Palestinian militants Hamas into Israel was the pretext for the assault on Gaza, Israel appears to have learned from its mistakes when it waded into a costly war against Lebanese militant group Hezbollah in 2006.

"I don't think that Israel will go to war over firing three rockets," said Hilal Khashan, a specialist in international affairs at the American University of Beirut. He told Forbes.com that Hezbollah was clearly not behind the attacks because it had not issued a statement claiming responsibility. He added that the Lebanese government had already blamed Palestinians in Lebanon for the handful of rockets fired into Israel.

Oil prices, which had strengthened throughout the Israeli army's invasion of Gaza, did not react sharply to the developments. Crude futures in New York traded at $42.99 per barrel, up from $42.63, while the spot price of European Brent crude stayed flat at $45.76. The TA-25 equity index fell 2.2% in Tel Aviv, while most European national benchmarks were down 0.5%-1.0%.

A spokesman for the Israel Defense Forces also blamed "Palestinian sources" in Lebanon for trying to drag Israel's neighbor into a new war. "We see the Lebanese government and the Lebanese military as responsible for preventing fire at Israel," he told Forbes.com.

The Lebanese government has tried in the past to crack down on militant groups operating in Palestinian refugee camps, despite reports that Sunni Muslim politicians in Lebanon helped support and fund these groups for their own ends. In 2007, the Lebanese army besieged the Nahr al-Bared refugee camp in northern Lebanon and spent months trying to flush out the militant group Fatah al-Islam.