Izz El-Deen Sheikh Khalil
A "Israeli security source" tells the BBC that Israel killed Izz El-Deen Sheikh Khalil in Damascus:
An Israeli security source has told the BBC Israel was involved in the killing of a Hamas activist in Syria on Sunday.
Officially Israel has neither confirmed nor denied being behind the attack on Izz El-Deen Sheikh Khalil, whose car was destroyed by a bomb in Damascus.
Israel described him as a point man for the Palestinian Islamist movement's military actions in Gaza Strip.
Syria said Israel's attack showed its "intention to shake regional security and stability".
The Israelis had vowed to hit Hamas leaders "wherever they are" after suicide bomb attacks in August in Beersheba left 16 people dead.
Witnesses said they saw Mr Khalil get into his car and answer his mobile phone moments when the vehicle blew up. Three passers-by were injured.
Warning to Syria
Mr Khalil, 39, was a senior figure in Hamas' military wing and a member of the generation that set the group up.
He was based in Damascus along with other senior Hamas figures, including the overall leader, Khaled Meshaal.
He was among about 400 Palestinian militants deported by Israel to Lebanon in the early 1990s.
However, there are reports that Israel is denying responsibility:
Only weeks after Israel publicly threatened to take its war with the Islamic militant group Hamas onto Syrian soil, a Hamas official in Damascus was killed Sunday when a powerful explosion tore through his sport utility vehicle.
Israeli officials disavowed knowledge of the blast that killed 42-year-old Izzedine Sheik Khalil, who had lived in the Syrian capital for the last 13 years and was reportedly a member of the group's military wing.
Prime Minister Ariel Sharon's government expressed satisfaction over the death, and some news reports here cited security sources as indicating that Israel was responsible.
If so, it would be Israel's first known assassination of a Hamas operative outside the West Bank and Gaza Strip, though it has on rare occasions struck at prominent Palestinian militant leaders on foreign soil.
Syria, in statements carried by its official news agency, blamed Israel for the attack and denounced it as a terrorist act. But Israeli commentators said the likelihood of any direct Syrian military response was extremely remote, because of the vastly superior strength of Israel's armed forces.
Khalil died instantly when his four-wheel-drive vehicle exploded just after he climbed in and started it, according to witnesses and news reports from the scene. Al Jazeera and other Arabic-language television channels showed footage of smoking wreckage at the blast site, in the Zahraa district of Damascus.
Israel had explicitly threatened the group's Syria-based leadership after Hamas took responsibility for near-simultaneous suicide bombings Aug. 31 aboard two buses in the Negev desert city of Beersheba. Sixteen passengers died along with the two Palestinian attackers.