JERUSALEM, Israel -- When the Syrian uprising turned into a civil war in 2011, most of the trouble stayed inside Syria's borders, but that's changing.
This week armored personnel carriers rushed to Beirut, Lebanon, to prevent fighting between supporters and opponents of Syrian President Bashar al Assad. It's a sign the war has spread well beyond Syria's borders.
Another sign: at an election rally last Sunday, Turkish Prime Minister Tayyip Erdogan praised the Turkish air force for shooting down a Syrian plane after it violated Turkey's air space.
"If you violate our border, our slap will be hard. Therefore, I congratulate firstly our chief of general staff, and our pilots," Erdogan said.
Also last week, Israeli warplanes struck Syrian military posts in the Golan Heights after a roadside bombing wounded four Israeli soldiers. It was some of the worst fighting on Israel's border with Syria in decades.
Israel doesn't want a war with Syria, and Prime Minister Benjamin Netanyahu's government has tried to steer clear of the fight between Assad and his opposition. But the conflict is expanding anyway.
"I think we can already consider now that the Israeli-Syria border is back, is a conflict border once again," Middle East expert Jonathan Spyer, with the Gloria Institute, said.
"And what we're going to see I think as in common with Israel's other conflict borders -- for example vis-a-vis the Hamas statelet -- is that we will have periodic rounds of violence in which the Hezbollah or the Assad regime or whoever it is or perhaps in other sectors of the border the Sunni jihadists on the rebel side will try and redress the balance against Israel," he explained.
Muslim rebel groups, some backed by al Qaeda, are gaining ground near the Turkish border. Recently, they entered a deserted Armenian Christian town.
"Victory from God, we shall soon conquer!" they shouted.
A short time later, they gained their first foothold on the shores of the Mediterranean.
Meanwhile, Israel has been treating Syrians injured in the fighting.
In February, Netanyahu visited a field hospital and met with some of the Syrian wounded. He also pointed to Iran as Assad's chief sponsor in the widening war.
"Who is supplying these bombs? Who's supplying these weapons? Iran. Who's giving the instructions? Iran. Who's giving the backing for this butchery? Iran," the prime minister said.
Middle East analysts like Spyer warn an Assad victory in Syria is a victory for Iran.
"This would be an enormous victory for the Iran-led regional block. It would mean Iran then conclusively established of a single pro-Iranian block stretching effectively from western Afghanistan from the Iranian-Afghan border all the way to Mediterranean Sea," Spyer said.
"This would be an immense victory for the Iranians, and therefore, an immense defeat for the U.S. interests, which sees, or at least ought to see -- I'm not quite sure if the U.S. does right now see it this way -- but ought to see the Iranian regional block as the most potent and powerful challenge to Western interests and Western allies in the Middle East," he warned.