LBC International released footage of the incident, which took place while the channel was live on air. The explosive was thrown into the car park, damaging one vehicle, although no injuries were reported.
LBCI said CCTV footage showed two people riding a motorbike, who are now the main suspects. A motive has yet to be established but last week the channel broadcast a comedy programme that appeared to mock Lebanon’s Shiite people.
The latest attack has been widely condemned, with Prime Minister Najib Mikati saying media freedom must be safeguarded and pledging to step up the investigation into the incident.
Information Minister Ziad Makary described the attack as “reprehensible”.
Last month Lebanese channel Al Jadeed was targeted three times in four days. Again, while no motive has been confirmed, the attacks came after it had broadcast a sketch deemed by some to be deeply offensive towards the Shiite community in the south of the country.
Lebanon plummeted in Reporters Without Borders' 2022 report, falling to 130th worldwide, from 107th the previous year.
“Public opinion is predominantly conservative and some topics are taboo, such as criticism of cultural and religious heritage,” its report said. “Misogyny and racism are common, and women journalists are often targeted by defamation campaigns.”