TRIPOLI, LEBANON -- Syria’s civil war is inflaming passions next door in Lebanon. James Brooke reports from Lebanon’s second largest city, Tripoli, where supporters and opponents of Syrian President Bashar al-Assad fought running gun battles last week.

Posters of Syrian President Bashar al-Assad festoon this hilltop neighborhood overlooking Tripoli, Lebanon’s second largest city.

This one reads: “The Arab nation will not kneel as long as Bashar al-Assad is their Commander.”

But Abo Ali Zoumar, a local militia commander, admits it has been five years since he has gone down the hill to the Mediterranean shore, only one kilometer from his apartment.

Blocking his way are militia from Tripoli’s Sunni majority population. They back the rebels in neighboring Syria.

Last week, Syria’s civil war spilled over into Lebanon, as fighting broke out between the two groups here, killing 17 and wounding 77 more.

In Tripoli, Lebanon, the Lebanese army has imposed a ceasefire after fighting here between supporters and opponents of Syrian President Assad. This man was one of 20 volunteers killed with rebels inside Syria.

With the Syrian border only 30 kilometers north of here, the Lebanese men went to help their fellow Sunni in the ranks of the Free Syrian Army.

On Syria Street, the border between the two warring communities,

Sheikh Walid Taboush is the imam of Tabbaneh.  He believes that his enemies up the hill collaborate with Syrian intelligence.  They are from the same Alawite sect as the al-Assad clan that rules Syria. The imam says Lebanon’s Alawite minority must break its ties with Syria’s rulers now, before the regime collapses.

“We have heard from France, America and Russia that is possible that  Syria will be divided, that Bashar al Assad will go to Tartus and Latakia and form the Alawi state in Syria. This will have a negative effect on the whole Arab region, not only on Tripoli," he said.

In a rare interview,  Zoumar, the Alawite militia commander, says his Sunni neighbors radicalized in recent years:

“They got Islamic features, with beards and mustaches, and dressed like Bin Ladin. They became fanatic and started to denounce others in the mosques and on TV. We were used to them, we were brothers living together," he said.

Showing a photo of his three-year-old old son with an AK-47 rifle, Zoumar says hefights to protect Alawites against ethnic cleansing by Sunnis:

Down the hill, Lebanon’s Army now patrols Syria Street, keeping a close eye on both sides.

Abdul Hamid Sidawi, looks at the charred remains of his vegetable stand. He recalls Lebanon’s 15-year civil war that ended in 1990.

“I was 23 years old when the war started in 1975. And now it is the back with our children," he said.

Lebanon’s Army may be the best hope for stopping violence spreading here from neighboring Syria.