In a hit claimed by Israeli security officials, a senior Hamas operative was killed in a car bombing Sunday outside his house in Damascus, the first such killing of a leader of the Islamic militant group in Syria.
Izz Eldine Subhi Sheik Khalil, 42, died instantly in the explosion, which wounded three bystanders. Witnesses said he was speaking on his mobile phone as he put his white Mitsubishi SUV in reverse before it exploded about 10 yards from his home.
Analysts said the killing appeared designed as much to warn the Syrians as to keep Hamas off balance.
Syria called the killing "cowardly" and top Hamas leaders, taking extraordinary security precautions, went deeper underground. The killing threatened to take the Palestinian-Israeli conflict to new levels, with conflicting remarks from Hamas on whether it too would begin targeting Israeli interests abroad.
Security officials in Jerusalem acknowledged involvement, though the Israeli government issued no statement. It had been warning for weeks that members of the group would not be safe in Syria.
Israel's ability to infiltrate the Hamas leadership in Damascus is likely to further rattle the group after Israel killed Hamas founder Sheik Ahmed Yassin and his successor as Gaza leader, Abdel Aziz Rantisi, in missile strikes this year.
The Syrian Interior Ministry said in a terse statement carried by the official news agency, SANA, that Khalil had not engaged in any militant activity inside Syrian territory, and authorities were investigating the explosion.
Ahmad Haj Ali, an adviser to the Syrian information minister, described the assassination as a "terrorist and cowardly action."
"This is not the first warning" Israel has tried to convey to Syria, Haj Ali said. "What happened indicates that Israel's aggression has no limits."
The killing also was a clear warning to top Hamas officials, who have stayed largely out of sight since Sept. 2, when the group claimed responsibility for the Aug. 31 twin suicide bombing in southern Israel that killed 16 Israelis. Hamas has carried out numerous suicide bombings and killed hundreds of Israelis. After the Beersheba attack, Israel warned Syria that it was ultimately responsible for actions of the groups it sheltered.
Hamas leader Khaled Mashaal, who has been based in Damascus, resurfaced in Cairo, Egypt, last week but would not say where he was going. Syria has denied evicting him from Damascus.
A Hamas statement published on the group's Web site said Israel "has opened a new door for the struggle by transferring the battle outside the land of Palestine," hinting it might expand operations against the Jewish state to its interests outside Israel.
But a Hamas spokesman in Lebanon, Osama Hamdan, denied any decisions have been made.
"There is no change in the policies of Hamas," he said.
The group's militant wing in the Gaza Strip would decide on retaliation, which Hamdan said will come at the "appropriate time and place."
Khalil may have been targeted because he lived outside the well-guarded Yarmouk Palestinian refugee camp. His home was on the ground floor of the 10-story building in al-Zahraa, where he moved with his family about a year ago. On Friday, the London newspaper Al-Hayat reported that an Arab intelligence service had given Israel information on Hamas leaders abroad, including where they lived, what their hobbies were and even what food they ate. It cited unidentified Arab sources in Europe.