A Lebanese security source said Hezbollah spokesman Mohammed Afif was killed in an Israeli strike Sunday in central Beirut that hit the Lebanese branch of the Syrian Baath party.
"The strike on Ras al-Nabaa killed Hezbollah media relations official Mohammed Afif," the security source said, requesting anonymity as they were not authorised to brief the media.
Ali Hijazi, secretary-general of the Lebanese branch of the Baath party, "confirmed the death of Hezbollah media official" Afif, the official National News Agency reported.
The Israeli army declined to comment.
Lebanon's health ministry said the strike killed one person and wounded three others, adding that the toll was provisional and that work was ongoing to remove rubble from the site of the strike.
Afif for years had been responsible for Hezbollah's media relations, and provided information to local and foreign journalists under the cover of anonymity.
The NNA said the strike by "enemy aircraft" caused "great destruction", reporting an unspecified number of people "trapped under the rubble" in Ras al-Nabaa, an area near the French embassy and a university.
It said "one of the residents of a neighbouring building had received a warning call urging evacuation but it was not taken seriously".
Since the assassination in late September of longtime Hezbollah chief Hassan Nasrallah in a huge Israeli strike, Afif had held several press conferences in Beirut's southern suburbs.
In one such event last month, Afif announced that Hezbollah had launched a drone targeting the residence of Israeli Prime Minister Benjamin Netanyahu.
That press conference was cut short when the Israeli army warned it would strike a building nearby.