Saudi Arabia’s execution of Shi’ite cleric Nimr al-Nimr seems likely to escalate sectarian Sunni- Shi’ite violence in the Middle East, experts told The Jerusalem Post on Monday.Gulf Sunni states, with the exception of independent- minded Oman, are expected to publicly back the Saudis, while Shi’ite-dominated Iraq and allied Syria back Iran.“The Shia Sunni conflict is boiling,” Eliezer “Geizi” Tsafrir, a former Arab affairs adviser to the prime minister and senior Mossad and Shin Bet (Israel Security Agency) official, who is currently a fellow at the Institute for Counter-Terrorism (ICT) at the Interdisciplinary Center (IDC), Herzliya, told the Post.“Backed by petro-dollars and aggressiveness” revolutionary Iran is supporting its allies throughout the region and the “Sunni world is terribly afraid of the Iranian threat, perhaps dreaming that the US or Israel will do the job,” Tsafrir said.Tsafrir pointed at how tensions were already rife since the Saudis, having had enough of Iranian subversion near its border, launched a war in Yemen last year to defend its interests against Iranian- backed Houthis taking over the country.Tsafrir added that the decision by Sudan, until recently in Iran’s orbit of influence, to cut off diplomatic relations with the Islamic Republic, may be a sign of things to come. He said Khartoum’s maneuver demonstrated how far the conflict between the Sunni and Shi’ite factions has escalated.“We can expect more steps,” Tsafrir said.Prof. Joshua Teitelbaum, an expert on Saudi Arabia and the modern Middle East, told the Post that since King Salman took over a year ago, “he and his advisers have pushed for a more muscular foreign policy to assert Saudi responsibility for Sunni Muslims.”In addition, Teitelbuam, a senior research associate at Bar-Ilan University’s Begin-Sadat Center for Strategic Studies, sees Saudi action as a response to American retrenchment in the region.“The Saudis perceive it as creating a vacuum that the pro-Iranian Shi’ite forces are filling,” Teitelbaum said.The latest anti-Iranian Saudi moves can also be seen as a step by the young new Saudi defense minister, Sheikh Mohammed bin Salman, the king’s son, as seeking to prove his mettle, Teitelbaum said.Meir Javedanfar, a lecturer on Iranian politics at the IDC said that both sides “are going to significantly increase support for proxy groups in Syria, Yemen, Iraq, and even Lebanon.”“This is going to make the job of [Secretary of State] John Kerry of finding peaceful solution in Syria much more difficult,” Javedanfar said.Asked if he envisages direct military conflict between Iran and Saudi Arabia, Jevadanfar responded that for now direct confrontation is unlikely as they “prefer fighting proxy wars against each other. And this is likely to continue.”Dr. Michael Barak, a Middle East senior researcher at ICT and a lecturer at the IDC’s Lauder school of government diplomacy and strategy, said that “Saudi Arabia crossed an Iranian red line by executing Nimr, which humiliated Iran.”In recent years, Iran warned Saudi Arabia not to execute Shi’ite clerics, but the Saudis were determined to act against Shi’ite terrorism, Barak said.“The execution of Nimr and three other Shi’tes is a declaration of war against Iran,” Barak said. He predicted Iran would respond “in the near future, perhaps by assassinating a prominent Saudi figure such as an ambassador.”Barak said Iranian authorities have also arrested clerics from its Sunni minority and could execute them in revenge. Another possibility, he said, is that Iran may use its proxy in Yemen, the Houthis, to launch more attacks on Saudi Arabia.