Hezbollah leader Hassan Nasrallah said on Thursday that Israel's Mossad espionage agency was behind the 2008 assassination of the Lebanese militant group's deputy leader Imad Mughniyah.

The reclusive Nasrallah said this was the conclusion of an investigation into the car bombing in Damascus that killed Mughniyah, who was on the U.S. most-wanted list for attacks on Israeli and Western targets.

"The day won't come when we'll put the blood vengeance for the martyr Mughniyah behind us," said Nasrallah, vowing that his organization would avenge the assignation.

Nasrallah made the comments via a video link from his hiding place.

The Hezbollah leader also said there was no difference between United States President Barack Obama and his predecessor George W. Bush when it comes to Israel.

"The conduct of the new administration when it comes to Israel is ... one of absolute support, Nasrallah said."I have not sensed until now that there is any difference between the two [U.S.] administrations," he said in his first comments since Obama took office on January 20.

He denounced some European officials for allegedly fully supporting Israel during its recent 22-day military offensive against Hamas in Gaza, which he described as a military and political failure. The Hezbollah leader claimed that Israel failed to achieve its target of routing out militant Palestinian Hamas from the coastal strip.

Nasrallah also repeated his criticism of Egypt for keeping its border crossing with Gaza closed. He said Egypt was lying to the Arab and Islamic world when it said it opened the crossing.