Prime Minister Najib Mikati said there was no evidence that al Qaeda militants were operating in Lebanon, countering the defense minister's statement that the global network had sent operatives into the Lebanon-Syria border area.
Grappling with a nine-month anti-government revolt, Syria has blamed al Qaeda for a double car bomb attack on its capital last Friday that killed 44 people and wounded more than 100.
Lebanon has tried to distance itself from the events in Syria where the uprising started off in March as a wave of peaceful protests against President Bashar Assad but is now overshadowed by an armed insurrection.
"There is no firm evidence of an al Qaeda presence in (border area) Ersal," Mikati told journalists late on Wednesday, according to Lebanon's state National News Agency.
"The military entered Ersal after being informed there was a person in the area who was perhaps tied to an international terrorist group but there was no information about the presence of any organized groups or any particular organization."
Assad says he is combating Islamist terrorism steered from abroad - a sensitive issue for neighboring Lebanon.
Lebanese Defense Minister Fayez Ghosn said last week that al Qaeda insurgents were operating on the border disguised as Syrian opposition activists.
The interior minister later spoke out against the statement, denying there was an al Qaeda presence in Lebanon.
In his latest remarks, Mikati shrugged off the conflicting arguments as a difference of interpretation.
"It's not the first time there are differences of opinions inside the government," he said. "The interior minister said he had no information. The defense minister said he had some information but not complete proof."
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