It was not immediately clear who carried out the bombing in the city of Sidon or why the Palestinian, identified as Mohammed Hamdan, was targeted. Hamas in a statement blamed Israel for the "criminal" act that wounded Hamdan in his leg.
It is not clear what role Hamdan plays in the militant group, which has offices and members living in Lebanon. There are over 147,000 Palestinians living in Lebanon, most of them in the country's 12 refugee camps.
Several armed factions are based in the camps where the state has no jurisdiction. Rivalry between them often leads to clashes. The largest Palestinian refugee camp is located in Sidon.
The Lebanese military said the explosion was caused by a 500-gram (18 ounces) bomb that included ball bearings. A Lebanese security official said the bomb was placed under the car seat. The official, who identified Hamdan as a Hamas member, spoke on condition of anonymity because he was not authorized to speak to the media.
The official Lebanon News Agency said the explosion went off as Hamdan was getting into the car.
Sidon Mayor Mohammed Saudi said Hamdan was undergoing surgery at a local hospital. He was slightly injured, according to Shanaa.
Shehab, a Gaza-based Hamas news agency, quoted Ayman Shanaa, a Hamas official in Sidon, as saying Hamdan was "one of the movement's cadres."
The explosion badly damaged the vehicle, causing a large fire and sending black smoke rising above the port city, about 27 miles south of the capital Beirut. The explosion caused some damage to nearby buildings and cars. Security forces cordoned off the area and firefighters put out the blaze.
Yasser Ali, a member of Hamas in Lebanon, said he ruled out the attack was part of inter-Palestinian rivalry. He said Israel has been vocally critical of Hamas's presence in Lebanon recently "because it is a big force here."
Hamas' deputy political chief is believed to be living in Lebanon, after he was expelled from Qatar last year.
Hamas officials later visited Hamdan in the hospital. Senior Hamas official Ali Barakah told reporters that the attack on Hamdan was an attack on "the Palestinian presence in Lebanon and on the sovereignty" of the country. He blamed Israel.
In 2006, two members of the Palestinian Islamic Jihad group were killed in the same neighborhood in Sidon when a bomb planted in a vehicle detonated as they passed near it. Israel was blamed for the attack. Lebanon is officially at war with Israel. The last war in 2006 ended in a stalemate.
Last year, another Palestinian official survived when he came under fire as he entered a residence in Sidon.
Political assassinations were common in Lebanon for years following the end of the country's civil war in 1990. But they have subsided in recent years and the delicate sectarian-based political system has largely been stable.
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