Al Qaeda, which originally announced its presence on the global scene in 1998 as "The World Islamic Front for Jihad against the Jews and Crusaders," for the first time has claimed an attack on the Jewish state from neighboring Lebanon.
Abu Musab Zarqawi, the commander of Al Qaeda's Middle East branch, issued a warning to Israel on the group's website, boasting that Katyusha rockets fired two weeks ago from southern Lebanon were just the "beginning of a welcome operation to strike deep in enemy territory, at the instructions of Osama bin Laden."
The statement was posted earlier this week on Internet sites associated with Jemaat al-Tawahid wal Jihad, Mr. Zarqawi's Sunni fundamentalist insurgents who are fighting the US in Iraq.
The claim of responsibility and its accompanying threat of more to come seem to realize concerns in Israel that over time Al Qaeda might step up attacks from neighboring Arab countries or from regions under control of the Palestinian Authority, analysts say.
After Israel withdrew its troops and settlers from the Gaza Strip in August, ending a 38-year-long occupation, Israeli officials expressed concern that Al Qaeda operatives had slipped in from Egypt during the course of several days of uncontrolled border crossings.
Moreover, the development also follows what may be a shift in strategy for Al Qaeda: While not giving up attempts to inflict massive attacks on major targets in the US and in Europe, it will take advantage of opportunities to hit targets in the Middle East.
These include the ongoing suicide bombings in Iraq's deadly insurgency and attacks on pro-Western forces in the Arab world - from international targets in Saudi Arabia to the triple bombing attack on three major hotels in Amman, Jordan on Nov. 9, 2005.
The attempt to ratchet up tensions on the Israel-Lebanon border comes at a time when the Israeli security establishment is concerned about the perception abroad of the country being in a state of political crisis, given that Prime Minister Ariel Sharon has been in critical condition for the past week.
"Zarqawi has tried to attack Israeli targets for a long time. We know for a fact that Al Qaeda has been pondering attacking inside the Israeli border, so it's nothing new, but we should see it as part of a trend," says Yoram Schweitzer, an expert on Al Qaeda at the Jaffe Center for Strategic Studies at Tel Aviv University.
"The reaction in Lebanon shows that even Hizbullah is a little bit frustrated," he adds, "not that they mind Israel being attacked, but they don't like anyone else trying to control their territory."
Indeed, the attempt of Al Qaeda operatives to gain ground in southern Lebanon, which has long been a magnet for militant groups, appears to have irked Hizbullah, or the Party of God, the primary military and political organization controlling the south of the country.
Hizbullah has moved toward a sort of hostile quiet with Israel during the more than five years since Israel withdrew from its occupied "security zone" in Lebanon.
It appears likely, many observers say, that the attacks were perpetrated by Palestinian militants who would like to link their agenda with Al Qaeda's.
Although Shiite Hizbullah, backed by Iran, tends to have good relations with mainstream Sunni groups in Lebanon, it is very worried about the emergence and spread of militant Sunni ideology and has been keeping a close eye on its presence in Lebanon.
"There are some [operatives] in Lebanon," says Sheikh Naim Qassem, Hizbullah's deputy secretary-general in an interview with The Monitor. "We don't know how many and we don't know their plans or if they intend to do [military] operations here," he says.
"It's important to caution everyone not to make Lebanon an arena for settling scores," he adds. "It will be a dangerous development if that happens."
Hizbullah, which maintains tight control of the border district, is opposed to outside actors staging attacks into Israel in case it upsets the delicate balance. Still, Hizbullah admits it is difficult to fully control the border region to prevent other militants from launching their own operations.
"I have read articles saying that attacks can only happen [in the border district] with Hizbullah's knowledge. This is not true," says Mr. Qassem, who says his organization is still investigating the Al Qaeda claim.
"Small groups can infiltrate in and out very quickly. Weapons are available everywhere. It's not complex. These are not large groups of people. Just two or three who plan for a while and then launch several rockets," he says.
The statement attributed to Al Qaeda used language that is similar to that employed in leaflets written by Palestinian groups such as Hamas and Islamic Jihad.
"The rockets fired at the grandchildren of monkeys and pigs from the south of Lebanon was only the start of a blessed in-depth strike against the Zionist enemy," the group said in a statement, which was posted on several different militant Islamic websites and picked up by both Western and Middle Eastern media outlets.
"All that was on the instructions of the sheikh of the mujahideen, Osama bin Laden, may God preserve him," said a taped voice that is reported to be Jordan-born Zarqawi's.
The tape also said that Israelis should not enjoy security as long as Muslims were not safe.
The Israeli Army could not comment in depth on the issue at this time. "As far as we are concerned, we hold the Lebanese government responsible for any activity that happens in its territory," a spokesperson for the Israel Defense Forces said.
"If the Lebanese won't move [against such operatives] and the Syrians won't do anything, we might run into a pattern," says Zeev Schiff, a top military affairs columnist for the Haaretz newspaper. "I can guess that if Sharon were really in power, this could be the time to act against" militants in southern Lebanon.