A suicide car bomber reportedly killed three people at a checkpoint manned by the Shia group Hezbollah in eastern Lebanon, the state-run news agency reported.
However, a Hezbollah-run TV station reported later on Saturday that the suicide bomber did not kill anyone at the checkpoint in the Bekaa Valley. There was no immediate way to reconcile the contradictory reports.
The bomber detonated his explosives-rigged vehicle at the checkpoint about 5km from the Syria border near the town of Khreibeh, Lebanon’s National News Agency said.
It was not immediately clear if the reported casualties were bystanders or Hezbollah fighters.
Since July 2013, dozens of people have been killed in more than a dozen suicide car bombings that have rocked the country.
The attack on Saturday was likely linked to the conflict in Syria, as the spillover from the war raises sectarian tensions in the Mediterranean country, where Sunnis and Shia back opposing sides of the neighbouring conflict.
Sunni fighters, including the Islamic State in Iraq and the Levant (ISIL), have been trying to punish the Iranian-backed Hezbollah because its fighters are battling alongside forces loyal to Syrian President Bashar al-Assad.
They have claimed responsibility for previous bombings in Lebanon that have targeted Shia communities. But they have also increasingly targeted the Lebanese army itself, seeing it as aligned with Hezbollah fighters.
Tensions have ratcheted further in recent weeks, after fighters from Syria overran a Lebanese border town, Arsal, in early August, capturing and killing soldiers and police.
The fighters, including the al-Qaeda linked Nusra Front and ISIL, are holding about 20 Lebanese hostages.
At least three have been killed by their captors. Two have been beheaded by ISIL, sparking days of violence against Syrian refugees in Lebanon and tit-for-tat kidnappings between Sunnis and Shias.