BEIRUT (Reuters) - Eight suicide bombers attacked a Lebanese Christian village on Monday, killing five people and wounding dozens more, in the latest violent spillover of the five-year-old Syrian war into Lebanon.

Security sources said they believed Islamic State was responsible for the bombings in the village of Qaa on Lebanon's border with Syria, but there was no immediate claim of responsibility.

A first wave of attacks involved four suicide bombers who struck after 4 a.m., killing five people, all civilians.

The first bomber blew himself up after being confronted by a resident, with the other three detonating their bombs one after the other as people arrived at the scene. The Lebanese army said four soldiers were among the wounded.

A second series of attacks, involving at least four bombers, took place in the evening as residents were preparing the funerals of those killed earlier. Two of the four bombers blew themselves up outside a church, security sources said. Nobody was killed. Medics put the number of injured at 15.

"It is clear from the pace of explosions that we have entered an episode from hell," Wael Abu Faour, the health minister, told Reuters.

In comments to local media, the head of the Qaa local council urged residents to stay at home and shoot anyone suspicious. The provincial governor meanwhile imposed a curfew on Syrian refugees in the area.

Lebanese security services have been on heightened alert for militant attacks in recent weeks. Islamic State had urged its followers to launch attacks on "non-believers" during the Islamic holy month of Ramadan, which began in early June.

Lebanon has been repeatedly jolted by militant attacks linked to the war in neighboring Syria, where the powerful Lebanese Shi'ite group Hezbollah is fighting in support of President Bashar al-Assad.

Hezbollah leader Sayyed Hassan Nasrallah on Friday warned of a threat posed by militants based in the border area between Syria and Lebanon, saying they were still preparing car bombs in the area.

(Additional reporting by Reuters TV; Writing by Tom Perry and Laila Bassam; Editing by Andrew Roche)