In an ambush on Sunday at a funeral procession in the south of Lebanese capital Beirut, a Lebanese security source said.
Several people were wounded in the exchange of the fire between members of the Lebanese Shiite group and Sunni residents, in the Khalde area.
At least five people including three Hezbollah members were killed in the ambush. The funeral procession was for a Hezbollah man who was killed a night before.
A military source told AFP the army had deployed to the area and sent reinforcements.
The army said in a statement that soldiers would "open fire on all armed men on the streets of Khalde" and in response to any other shootings.
Despite the warnings, sporadic gunfire lasted for about three hours after the violence erupted, according to an AFP photographer. A precarious calm set in during the evening.
Military checkpoints backed by armored vehicles were erected at various road crossings leading to Khalde.
The Lebanese Red Cross told AFP it transported four wounded people, including one in serious condition, for medical care.
"But the number of wounded is higher, as many were transported in private cars while the Red Cross was not able to gain access to the scene of the clashes," a Red Cross spokesman said.
A grouping of Arab Sunni tribes in Lebanon also issued a statement saying they did not want to be drawn into an armed confrontation but blamed Hezbollah for the troubles and accused it of stirring sectarian tensions.
Local television networks showed footage of armed youths rampaging in the area. The army, which sent reinforcements to Khaldeh, said it would shoot at any source of gunfire.
Source: Agencies