By Samia Nakhoul and Dominic Evans
BEIRUT (Reuters) - Lebanon's fractious communities will "all drown" together if they let Syria's civil strife spill over the border, the prime minister warned, as he called on factions to resist seeking partisan advantage from the violence.
Speaking to Reuters, Najib Mikati acknowledged the Lebanese are deeply divided over the uprising against Syrian President Bashar al-Assad, which has taken an increasingly sectarian turn and drawn in rival regional and world powers on opposing sides.
But in an interview late on Tuesday he cautioned: "If this crisis reaches Lebanon, there will be danger for all Lebanese.
"Nobody should think that he will benefit and the other party will be in danger. We are all in one boat and if it takes on water in this ferocious storm sweeping the region we will all drown," added Mikati, a moderate figure who gets on with rival regional powers Syria and Saudi Arabia and with Western states.
Mikati, who spoke at the Ottoman-era Grand Serail government building overlooking the rebuilt heart of once war-torn Beirut, has struggled to insulate his small nation from the bloodshed in its larger, and long dominant, neighbor. It is a task made nearly impossible by the close historic ties between Beirut and Damascus, and by Lebanon's own sectarian divisions.
U.N. Secretary-General Ban Ki-moon warned on Tuesday that the Syrian fighting risked spreading across the Middle East: "The entire region is being engulfed by the complex dynamics of the conflict," he told the General Assembly in New York.
Many of Mikati's fellow Sunni Muslims in Lebanon actively support the mainly Sunni revolt against Assad, who follows the minority Alawite faith which has links to Shi'ite Islam. Lebanese Shi'ites, among them the Iranian-allied militant group Hezbollah, mostly back Assad, who has support from Tehran.
Fighting in Mikati's home town of Tripoli between an Alawite minority and a Sunni Muslim majority has rekindled fears of renewed strife in Lebanon, which from 1975 endured 15 years of civil war that saw regional players Israel, Syria, Iran and the Palestinians all use it as a proxy battleground.
In New York, Ban raised the alarm about "unintended consequences" of outsiders taking sides in a Syrian conflict which he described as having "taken a particularly brutal turn".
"The continuing militarization of the conflict is deeply tragic and highly dangerous," he said. "Those who provide arms to either side are only contributing to further misery - and the risk of unintended consequences as the fighting intensifies and spreads."
World powers are deadlocked in the United Nations Security Council along Cold War lines, with the United States and its NATO allies supporting the call for Assad to quit and Russia and China defending him against what they see as outside meddling.
Visiting Beijing, U.S. Secretary of State Hillary Clinton reiterated Washington's view that the Assad family's days in power were numbered; her Chinese counterpart stressed, however, that a "transition", however welcome, should not be imposed.
"We and many countries all support a period of political transition in Syria," Chinese Foreign Minister Yang Jiechi said.
"But we also believe that any solution should come from the people of Syria and reflect their wishes.
"It should not be imposed from outside."
While Western powers say their aid to the rebels remains limited to supplies other than weapons, Sunni Arab states have supported arming the insurgents, while U.N. monitors have said Iran has transferred armaments to Assad's government.
Mikati said his government was doing what it could to meet Syrian demands that Lebanon prevent arms shipments reaching the rebels across its territory: "It is regrettable that anyone can use Lebanon as a tool to threaten the other," he said.
Pointing to the interception of a ship carrying weapons and the fact that some other consignments were seized at Beirut airport, he said: "Lebanon is carrying out its duties fully."
Of sectarian kidnappings that have revived painful memories of Lebanon's long suffering, he said: "We are passing through difficult circumstances and the entire region is boiling. Unfortunately, some elements feel they can undermine the state."
He insisted the Lebanese state "will bring to justice all those who are sabotaging security". But state institutions are themselves a fragile product of compromises among powerful factions which are being strained by the violence next door.
Egypt's new Sunni Islamist head of state, Mohamed Mursi, continued his drive for a dynamic role for newly democratic Egypt in regional diplomacy. As president of by far the biggest Arab nation, Mursi said at the Cairo headquarters of the Arab League that it was time for Assad to accept it was time to go.
Announcing a first meeting of a quartet of regional powers - Egypt, Iran, Turkey and Saudi Arabia - to try to forge a consensus, Mursi said Assad had missed his chance to satisfy his critics with promises of limited political reform:
It was, he said, time for "change and not wasting time speaking of reform". Addressing foreign ministers of the Arab League, which has suspended Syria's membership, he said: "This time has passed now. Now it is time for change."
In Syria itself, where the United Nations estimates some 20,000 people have been killed in the nearly 18 months since popular protests began, rebels besieging a military airport near the Iraqi border said they were engaged in heavy fighting and another group claimed to have shot down a jet fighter.
A spokesman for the group in Idlib province, close to the Turkish border, said a MiG-21, an ageing, Soviet-built aircraft, had been brought down by rebel machinegun fire as it tried to take off. Video posted on the Internet showed fighters celebrating around a MiG-21 tailfin and some burning wreckage.
It also showed the body of what appeared to be a pilot strapped to a parachute. The report could not be verified.
(Additional reporting by Erika Solomon in Beirut; Writing by Alastair Macdonald; editing by David Stamp)