A previously unknown group threatened action Monday during Iranian President Mahmoud Ahmadinejad's planned visit to Lebanon this week, local media reported.
A statement by a group calling itself the Abdaullah Azzam Brigades warned: "The whole of Lebanon will tremble and its ground will quake if Ahmadinejad steps foot on it.", dpa reported.
"We will do the impossible to thwart this" the statement added.
Ahmadinejad is due to pay an official two-day visit to Lebannon on Wednesday and Thursday, during which he will hold talks with Lebanese officials and tour areas near the Israeli-Lebanese border.
The visit of the Iranian leader comes as Hezbollah threatens a fresh round of violence in Lebanon stemming from the UN tribunal investigating the 2005 assassination of Muslim-Sunni former Prime Minister Rafik Hariri.
That threat comes after reports indicated that the tribunal planned to indict Hezbollah members in the bombing attack.
Iran gives extensive financial and military support to the Lebanese Shiite movement Hezbollah, which forms the parliamentary opposition to the western-backed government, led by Saad Hariri, son of the slain Hariri.