No one has claimed responsibility for the attacks, and Lebanon's moderate, pro-Western prime minister, Fouad Siniora, condemned them. Lebanese officials speculate that they are the work of militant Palestinian groups that operate from within the several Palestinian refugee camps inside Lebanon. The Iranian-backed Shiite group Hezbollah said Wednesday that it wasn't responsible for the attacks.

Automated calls in Arabic warned residents of Beirut and southern Lebanon not to retaliate against Israel, as images of dead Palestinian children in Gaza flickered across Arabic news broadcasts in Lebanon, fueling resentment and anger at Israel. The Lebanese army sent special forces to the south to beef up security.

The government said all Lebanese factions, including rival party Hezbollah, had a consensus not to drag the country into another war with Israel.

"The risk is always there that things can quickly escalate, but these are really the acts of people outside the government. It's not accepted by us whatsoever and clearly we don't want to open this front," said finance minister Mohamad Chatah, a close adviser to Mr. Siniora.

Lebanon, despite its tiny size, is regarded as a key element in stabilizing the region. It has often been the place where regional powers such as Iran, Syria and Saudi Arabia fought out their grievances against each other and against Israel and the U.S.
The country is just starting to recover from two years of political standoff and a period of violent clashes in 2008 between Hezbollah and the U.S.-backed Sunni political party aligned with Mr. Siniora. When consensus for a government was reached in May, Hezbollah gained veto power, delivering a blow to the U.S.'s influence in Lebanese politics.

Mr. Siniora has been eager to show Lebanon can act as one state. He struck a cease-fire deal between Hezbollah and Israel after a month-long conflict in 2006 by vowing to implement a United Nations Security Council resolution that mandates the south, a Hezbollah stronghold, be policed by the Lebanese army and U.N. forces.

The threat of rogue elements in the south could hurt Mr. Siniora. Lebanon will have parliamentarian elections in June and all parties, including Hezbollah, have been campaigning on their ability to rebuild and unite the country.

"Everything we have built in the past few years is at stake. If the frequency of the attacks increases, if there are any casualties on both sides, we have a lot to lose," says Oussama Safa, director of the Lebanese Center for Policy Studies in Beirut.

In Gaza City, Israeli soldiers engaged with Hamas militants in the densely populated streets. Rockets continued to strike Israel. Palestinian casualties reached over 1,000 Wednesday with 4,550 wounded, according to medical workers from Gaza's Ministry of Health. Thirteen Israelis have died, including 10 soldiers, according to Israel's military.

-- Joshua Mitnick in Tel Aviv contributed to this article.