The suicide bombing that killed top members of Bashar Assad’s inner circle “is a 7 on the Richter scale,” a senior defense official said Wednesday, predicting that Assad’s days were numbered as leader of Syria.A bomb in a Damascus security building on Wednesday killed Defense Minister Daoud Rajha, former defense minister and senior military official General Hassan Turkmani and Assad’s brother-in-law, Assef Shawkat. Syria’s interior minister as well as several other officials were seriously wounded in the attack. In the afternoon, Defense Minister Ehud Barak and IDF Chief of Staff Lt.-Gen. Benny Gantz held consultations with officers from Military Intelligence, Northern Command as well as the Military Advocate General’s Office to discuss the events.Barak spoke later Wednesday night with US Defense Secretary Leon Panetta and updated him on Israel’s concerns regarding the situation in Syria.“We believe that the assassination of the top Syrian government officials will speed up Assad’s downfall,” Barak told Panetta, who is scheduled to visit Israel later this month. “We are also closely tracking the possibility that Hezbollah will try to move advanced military platforms or chemical weapons from Syria to Lebanon.”In recent weeks, senior officials have said in meetings with foreign guests that Israel is particularly concerned about one of three scenarios. The first is concern about the transfer of Syria’s chemical weapons to a third party like Hezbollah.The second worrisome scenario is the fragmentation of the country, whereby certain parties, or even a lone gunman, may gain access to bases with chemical weapons or other weapons systems, and then try to use them against Israel. For example, there are concerns that tanks – or even airplanes – could fall into the hands of someone who will use them against Israel.The third scenario is the possibility that Assad – feeling his back against the wall – will decide to take Israel down with him, and as a result fire everything he has toward Israel.“The entire country is in shock, and has been in shock for a year-and-a-half, but what happened today is earth shattering,” a senior defense official said. “Assad is living on borrowed time. He won’t want to see himself hung in the town square.”Assessments in the Israeli defense establishment are that Assad might turn to Russia and ask for help in escaping the country.Russia has significantly bolstered its naval presence in the Mediterranean in recent weeks and remains a significant presence in the port city of Tartus.Vice Premier Silvan Shalom said on Israel Radio that Israel was preparing for all contingencies, but would not become actively involved in the developments in Syria. He said there were those who wanted Israel to get involved precisely so they can blame anyone receiving Israeli assistance for collaborating with Israel.