JERUSALEM (CNN) -- Iran is in an "open war" with Israel, President Shimon Peres said Monday, as he pointed the finger at Iran and Hezbollah for last week's bombing in Bulgaria that killed five Israelis.
In an exclusive interview with CNN, Peres said Israel will act to prevent further attacks.
Peres said Israel has "enough" hard intelligence to link the Bulgaria attack to Iran and its proxy Hezbollah, and believes more attacks are being planned as part of what he called an "open war against Israel."
Prime Minister Benjamin Netanyahu has said that Iran and the Lebanon-based Hezbollah movement were responsible for a number of attacks and attempted attacks against Israeli targets in Thailand, Georgia, India, Greece, Cyprus and other countries.
Asked whether the Bulgaria bombing and the other attempted attacks were revenge for the assassination of Iranian nuclear scientists, which Iran blames on Israel, Peres said that Israel has never claimed responsibility for the killings. But he noted that Israel has a right to prevent the killing of its citizens.
"We don't have an initiative of terror," Peres said. "We don't do it. But self-defense is the right and the must of every people."
He said Israel's policy is one of "prevention," rather than "retaliation."
"If you have enough information about a certain person which is a ticking clock that can explode a bomb that can endanger civilian life, clearly you have to prevent him from doing so," Peres said. He cited reports that the United States has killed as many as 3,000 people in drone strikes aimed at terrorist enclaves.
With neighboring Syria in a spiral of violence, Peres said Israel will be forced to seize Syria's chemical weapons if there is a risk that President Bashar al-Assad would use them against Israel or that the arsenal could fall into terrorist hands.
Over the weekend, Defense Minister Ehud Barak said he ordered the military to prepare contingency plans to attack Syria's chemical weapons arsenals, should the need arise.
"The use of chemical weapons is internationally forbidden ... and what do you do when somebody violates the law? You fight against it," Peres said. "You stop them. We shall not remain indifferent and tell them, 'Do what you want.'"
Asked how far Israel would go to secure Syria's chemical arsenal, Peres simply said: "Until it will stop being a danger."
The conflict in Syria has already led to nearly 80,000 Syrians fleeing to neighboring Jordan, Lebanon, Turkey and Iraq, according to U.N. relief agencies. So far, none have sought refuge in Israel -- and Peres said Israel wants to keep control of its borders amid the crisis wracking its longtime foe.
"What will happen if Syrian refugees try to cross the Israeli border? Will you help them?" CNN asked Peres.
"No," he replied.
"Will you shoot them?"
"We will prevent them. I mean, you don't go straight to the rifle. There are other means to prevent them. We should prevent it. Because it will be a double tragedy for them and for us. They will become homeless and we shall become defenseless."
"If the Syrians start to come over the border, will you stop them by force?"
"First of all, until now none of them asked to come in," Peres said. "If they will come by force, we shall stop them by force. If they shall come in without force, we shall stop them the way any country defended her border with civilian means."
When CNN noted that the potential refugees are trying to escape bloodshed in their own country, not invade Israel, Peres said, "If they want to escape, they first of all have to appeal, ask for permission. None of them did it."
Peres spoke a day after Israel marked the 40th anniversary of the 1972 Olympic Games in Munich, Germany, where 11 Israeli athletes and coaches were killed by terrorists.
While he wouldn't go into details, Peres said Israel is taking precautions to ensure Israeli athletes are not targeted at the London Olympic Games, which start later this week. He argued, however, that if Israeli intelligence services agents had been at Munich, they would probably have been able to prevent the attack.