Lebanon always seems on the verge of reigniting the ruinous civil war that lasted more than a decade in the 1970's and 80's. Political crisis, Hezb'allah throwing its weight around, and political assassinations have threatened to restart the sectarian conflict on several occassions of the past few years.

But the war in Syria has actually led to shooting between Sunnis and Shias and it may be only a matter of time before the sectarian militias make a comeback and the civil war begins in earnest.

Associated Press:

The Lebanese army brought tanks and commando forces into the northern city of Tripoli Sunday, where fighting with Muslim militants has intensified and spread to nearby areas.

Several tanks, armored personnel carriers and Humvees carrying commandos arrived on the edge of the Bab Tabbaneh neighborhood, where clashes were heaviest. Intense gunfire exchanges and sporadic explosions rang out across the neighborhood, the worst fighting Tripoli has seen for months.

The clashes, which broke out Friday night, have so far killed five soldiers, two civilians and wounded many others. It was not clear if there were casualties among the militants.

On Wednesday, troops killed three militants and detained a local leader in a raid in the northern Dinniyeh region, setting off the spark that led to the Tripoli fighting.

The Lebanese army said in a statement that troops attacked a school in the nearby town of Bhannine that gunmen were using. It said several militants were wounded while others fled, adding that troops found two cars rigged with explosives as well as well as weapons and ammunition.

The statement said troops are deploying in Bab Tabbaneh and responding to the gunfire "of terrorists."

State-run National News Agency said the troops are now in full control of Tripoli's northern suburb of Minyeh after arresting several gunmen.

Sunni militants inspired by al-Qaida and the Islamic State extremist group have killed and wounded several soldiers in a string of attacks in recent months.

The deadliest was in August, when jihadi fighters from Syria briefly overran the Lebanese border town of Arsal, capturing some 20 policemen and soldiers and killing several others. That attack was the most serious spillover of the civil war into neighboring Syria since the uprising there began in March 2011.

The army is more pro-Syria than a tool of Hezb'allah, although the Byzantine nature of Lebanese politics makes that a distinction without a difference. As Hezb'allah becomes increasingly militant, the Sunnis suffer the consequences. And while there are still voices on both sides calling for restraint, once the fighting starts, those voices will be pushed to the background.

Of course, Lebanon borders Israel and the IDF is keeping a careful watch on the situation. It is unlikely that Hezb'allah will seek to engage Israel in war while they are so committed in Syria. But the Sunnis are no friend of the Jewish state either and conflict could erupt for any number of reasons.

A situation that bears watching in the coming weeks.