Mazen Faqha, a senior member of Hamas, was shot and killed in Gaza on Friday. Hamas blamed Israel for the killing and threatened revenge.

Faqha was shot four times in the head by a silenced handgun while walking near his home in the Tel el-Hawa neighborhood  in southwestern Gaza.

“Hamas and its (military wing) hold (Israel) and its collaborators responsible for this despicable crime… (Israel) knows that the blood of fighters is not spilled in vain and Hamas will know how to act,” Hamas said in a statement reported by Reuters.

Khalil al-Haya, Hamas’s deputy chief in the Gaza Strip, said only Israel would have had something to gain from the death, Reuters added.

Thousands attended his funeral on Saturday, which was marked by calls of “Revenge”. Hamas Attorney General Ismail Jaber spoke at the funerals,  blaming Israel for the killing.

“This assassination has the clear marks of Mossad (Israel secret service),” he said.

Faqha was arrested by Israel for his part in a 2002 bus bombing that killed nine Israelis. He was a senior Hamas official in Judea and Samaria and was sentenced in 2003 to nine life terms. He was released in 2011 with more than 1,000 other Palestinian prisoners in exchange for IDF soldier, GIlad Shalit.