Israeli security sources acknowledged on Sunday that Israel was involved in the assassination of a senior Hamas official in the Syrian capital of Damascus, and Hamas vowed to strike Israeli targets in revenge.

Iz a Din al-Sheikh Khalil, 42, died when he started the engine and an explosive charge under the driver's seat ripped through his SUV in the Az-Zahera neighborhood of Damascus around 11 A.M. Sunday.

Khalil was considered to be Hamas' most senior operative in Damascus. Israel says he directed terror attacks and was responsible for coordinating operations with the military forces of Hamas in the West Bank and Gaza.

In a statement released in the Gaza Strip, Hamas appeared to threaten that the group will hit targets both in Israel and abroad.

The Syrian state news agency said Sunday night that the assassination was a "terrorist act" by Israel and called it "a grave development."

The militant Palestinian group vowed to strike back with terror attacks inside Israel. "There will be a response that would be decided by the movement's leaders inside the occupied territories," a Hamas spokesman in Damascus said.

In a statement, the group said that it "stresses that these crimes which unify the Palestinian blood inside and outside Palestine would not terrorize us or stop us from pursuing the path of jihad and resistance."

Hamas also appeared to threaten striking Israeli targets abroad.

"We have let hundreds of thousands of Zionists travel and move in capitals of the world in order not to be the party which transfers the struggle," said the statement by Iz a Din al-Kassam, the military wing of Hamas. "But the Zionist enemy has done so and should bear the consequences of its actions...