BEIRUT AND DHAIRA, LEBANON — Lebanese army and international forces bolstered troop numbers, stepped up patrols and declared a state of alert Thursday after an early-morning rocket attack on Israel from southern Lebanon threatened to widen the ongoing Gaza Strip conflict.
The rocket fire, which struck a nursing home and slightly injured at least two civilians, resurrected memories of the destructive 2006 war between Israel and the Shiite Muslim militia Hezbollah, an ally of the Gaza-based militant group Hamas.
Minutes after the attack, Israel responded by firing at least six artillery shells at the suspected launch site. Both Lebanese and Israeli authorities shut down schools in the area for fear of a military escalation as Israeli fighter jets flew low along the border.
There was no claim of responsibility for the rocket attack. Hezbollah and the major Palestinian organizations based in Lebanon denied any role. Only one small group, the Popular Front for the Liberation of Palestine General Command, would neither affirm nor deny any part in the attack.
"We hope that it won't become an action that makes the situation more complicated," Palestinian Authority President Mahmoud Abbas told reporters Thursday in Madrid as he toured world capitals in a quest for a Gaza cease-fire.
The Israeli army confirmed the rocket attack and return fire. A statement said Israel "regards the government of Lebanon and its army as responsible for preventing attacks on Israel."
Analysts said it was possible Hezbollah could have allowed a minor Palestinian group to launch the attack as a warning to Israel, or to test the Jewish state in a small but symbolic action to see whether it was gearing up for another round of battle in the two adversaries' long-running confrontation.
"They're slowly sending out feelers to test Israel's readiness for a possible war against Hezbollah," said Amal Saad-Ghorayeb, a British-Lebanese researcher and scholar who has written extensively about Hezbollah. "They're just playing a war of nerves with Israel."
The incident underscored the fragility of the peace along the Israeli-Lebanese border, and the mounting suspicions on each side that the other will widen the scope of the Gaza conflict, which began Dec. 27.
"It is safe to assume that Palestinian operatives, working in coordination with Hezbollah and sponsored by Iran, are responsible for the rocket attacks in Nahariya and elsewhere in the north," Yoav Stern, a correspondent for the Israeli daily Haaretz, wrote on the paper's website Thursday.
Southern Lebanon, which abuts northern Israel, has been patrolled by Lebanese army troops and a bolstered force of more than 12,000 United Nations troops known as the Interim Force in Lebanon, or UNIFIL, since the 2006 war between the Jewish state and Hezbollah, which, with its powerful militia and well-developed political organization and social services, is almost a state unto itself in Lebanon.
Rocket fire from the valleys and mountains of southern Lebanon into northern Israel has for decades been a source of regional friction and wars, beginning with Palestine Liberation Organization attacks and Israeli incursions in the 1970s. In Thursday's incident, three or more Katyusha rockets were fired from a valley between the villages of Dhaira and Tayra Harfa, a rural Hezbollah stronghold about four miles east of the coastal town of Naqoura and less than two miles from the Israeli frontier.
The rockets landed around the northern Israeli resort town of Nahariya shortly after 7:30 a.m., authorities in Israel and Lebanon said. As a UNIFIL helicopter scoured the area, Israel returned fire within 15 minutes, causing no injuries or damage, officials and witnesses said.
"It was an immediate response mechanism that shoots immediately at the location where the rockets came from," Andrea Tenenti, spokesman for UNIFIL, said in a phone interview from the organization's headquarters in Naqoura.
Residents of the sparsely inhabited agricultural region panicked as Israeli fighter jets flew above. Families rushed to fetch their children from school.
"Of course we got scared because this reminded us of the war in 2006," said Hossein Fouani, 21, a stone quarry employee who lives in Dhaira and survived the previous conflict huddling with relatives at a U.N. compound.
UNIFIL commander Maj. Gen. Claudio Graziano, who maintains contact with both Israeli and Lebanese authorities, called for "maximum restraint" by all parties. As evening approached, tensions between Israel and Lebanon appeared to ease, even as the fighting in the Gaza Strip continued to rage.
Experts say the attack, which employed older Katyusha rockets, bore the hallmarks of Palestinian groups rather than Hezbollah, which has an arsenal of newer, longer-range weapons.
"It's very possible that Hezbollah wasn't aware of the attack," Saad-Ghorayeb said.
Analysts note that some supporters of the Palestinian cause have accused Hezbollah of abandoning the fight.
"It could be that Palestinian groups are trying to corner Hezbollah and draw the group into a confrontation with Israel," said Sami Nader, a professor of international relations at the University of St. Joseph in Beirut.
Rafei is a special correspondent.