"He opened the door of his auto outside his home and the bomb went off", a source from Sidon said.
Mohammed Hamdan, a senior official in the Palestinian movement Hamas was reportedly wounded in an explosion of a vehicle on Sunday.
Hamas command committee member, Ayman Shanaa said that Mohammad Hamdan, who is also called "Abu Hamza" was transferred to hospital, noting that his injuries were minor.
A leader of the Palestinian Fatah movement in Lebanon said Hamdan was involved in operations in Israel.
Hamas did not immediately issue a statement on the blast.
Security forces cordoned off the area and firefighters worked to put out the blaze.
A medical source at the scene said Hamdan, also known as Abu Hamza, suffered serious wounds to his legs while opening the door to his auto, and was transported to hospital.
Hamas has fought three wars with Israel in the past decade and is based in the Gaza strip, but it operates branches elsewhere in the Middle East including Lebanon. The explosion took place at his home, near Sidon's Al-Bustan Street.