Israeli leaders warned Tuesday of threats posed by Iran, Hezbollah and their mutual ally Syria as the new Israeli parliament opened following last month's general election.
President Shimon Peres said the threat of a nuclear-armed Iran was growing under the "terrifying dictatorship" ruling the Islamic republic.
"The Iranian danger has grown," Peres said in a speech to the Knesset, or parliament. "It threatens our existence, the independence of the Arab states, the peace of the whole world."
"At its head stands a group of ayatollahs in their religious robes, a terrifying dictatorship, staining Persian history and a nightmare for its people," he told MPs.
Much of the international community fears Iran's nuclear programme includes efforts to develop nuclear weapons, a charge Tehran has repeatedly denied.
Israel believes Iran must be prevented from reaching military nuclear capabilities at any cost and refuses to rule out military intervention to that end.
It also accuses Iran of sponsoring the Lebanese militia movement Hezbollah, which Bulgaria said Tuesday was behind a bomb attack there in July that killed five Israeli tourists and one Bulgarian.
Israeli Prime Minister Benjamin Netanyahu said the Bulgarian finding should push the EU to draw the "necessary conclusions" about the Shiite group, a reference to Israel's longstanding demand it be placed on a terror watch list.
"The attack in Burgas was an attack on European soil, against a member state of the European Union," Netanyahu said. "We hope that the Europeans will draw the necessary conclusions about the true nature of Hezbollah."
"This is yet a further corroboration of what we have already known, that Hezbollah and its Iranian patrons are orchestrating a worldwide campaign of terror that is spanning countries and continents," he said.
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The bombing on a bus carrying Israelis at Burgas Airport on Bulgaria's Black Sea coast, the deadliest attack on Israelis abroad since 2004, also killed the Bulgarian bus driver and the bomber. Some 30 people were wounded.
"The attack in Burgas was just one in a series of terror attacks planned and carried out by Hezbollah and Iran," Netanyahu said. "That is in addition to the support that Hezbollah and Iran give to the murderous... regime in Syria.
Tehran has denied any involvement in the Burgas attack.
Peres said he was confident of US President Barack Obama's intent to thwart Iran's nuclear arms ambitions.
"The United States can put an end to the Iranian threat and I believe that the President of the United States is determined to do it," the Israeli president said.
He called on the United Nations and the Arab League to act urgently to end the turmoil in Syria.
"Iran is a danger and Syria is a tragedy. Its president butchers his people. In my opinion the UN should task the Arab League with the immediate formation of a transitional government in Syria to save it from self-destruction. Assad, who has murdered tens of thousands has also murdered his future," he said.
Syria has blamed Israel for a Wednesday air raid at a military complex near Damascus, which targeted surface-to-air missiles and an adjacent military complex believed to house chemical agents, according to a US official.
Damascus has threatened to retaliate and Syria's close ally Iran warned the attack would have "grave consequences" and that the "Zionist entity" would regret its aggression against Syria.
While Israel has not yet formally confirmed its responsibility, Defence Minister Ehud Barak on Sunday dropped a heavy hint.
"It's another proof that when we say something we mean it," Barak told reporters at a security conference in Germany.
"We say that we don't think that it should be allowable to bring advanced weapon systems into Lebanon, the Hezbollah, from Syria, when Assad falls."