Story highlights Top official says Israel has been trying to prevent Iranian attacks for years

A bomb blows off one man's leg in Bangkok as he flees police

Three men flee a Bangkok house after an explosion

Israel is on a heightened state of alert

Israel's defense minister blamed Iran for a series of bombings in the Thai capital of Bangkok Tuesday, a day after attacks against the country's diplomats in India and Georgia.

"The attempted terror attack in Thailand proves once again that Iran and its proxies continue to operate in the ways of terror and the latest attacks are an example of that," said Defense Minister Ehud Barak, who issued the statement from Singapore, where he is currently traveling.

"Iran and Hezbollah are unrelenting terror elements endangering the stability of the region, and endangering the stability of the world," Barak added.

Two Iranians are now in custody in Thailand and another person is at large, the government said. Five people were injured, authorities said.

The first bomb went off in a rental house, believed to be leased by three foreigners, according to Thai Police Maj. Gen. Pisit Pisutthisak.

JUST WATCHED Bombs planted on Israeli embassy cars Replay More Videos ... MUST WATCH Bombs planted on Israeli embassy cars 03:24

JUST WATCHED Iran: Israel working with terrorists Replay More Videos ... MUST WATCH Iran: Israel working with terrorists 02:41

The three fled after the blast. Two of the men left the scene, he said. The third man detonated two more bombs -- one when a taxi driver refused to give him a ride, and another when he tried to throw a bomb at police as they closed on him.

The last bomb exploded near the man, blowing off one of his legs, Pisit said. He was taken to Chulalongkorn General Hospital for treatment.

Thai government spokeswoman Thitima Chaisaeng said the man in the hospital is Iranian, and that Iranian documents were found on him.

Another man arrested at the airport is holding an Iranian passport and is one of the three, Thitima said. He was identified as Mohammad Hasai, 42, and was about to leave for Malaysia, she added.

Thitima told CNN that Thai intelligence agencies don't think the incident was an act of terror because it was carried out in a sporadic way. But, she said, police think that the men may have been selling weapons and drugs.

Israeli Foreign Ministry personnel based overseas have been on alert in recent weeks to the heightened possibility of attacks at Israeli facilities by Hezbollah, the Lebanese Muslim militant group and political party backed by Iran.

Sunday marked the fourth anniversary of the death of Hezbollah leader Imad Mugniyah in a car bombing in Damascus, Syria. Hezbollah holds Israel responsible for his death and has vowed revenge.

Israeli police spokesman Micky Rosenfeld told CNN that the level of alert in the country had been raised following a security assessment after the overseas incidents in New Delhi and Tbilisi, the capitals of India and Georgia.

The alert means patrols will be heightened in and around various public areas inside Israel, and around Israeli embassies and offices worldwide.

In the Monday incidents, a device attached to an Israeli Embassy van in New Delhi exploded and injured four people. Another device was found on an embassy car in Tbilisi, Georgia, but it was safety detonated.

The Israeli government issued a travel advisory this year for citizens traveling to Thailand after Thai security officials arrested a man in January connected with a planned attack in the country.

The police charged the man, Atris Hussein, after finding "initial chemical materials that could produce bombs" in an area just outside Bangkok. Police said Hussein, who also holds a Swedish passport, led them to the location.

The authorities are accusing Hussein of trying to attack spots in Bangkok that are popular with Western tourists and say he is believed to belong to Hezbollah, the Shiite Muslim group active in Lebanon that the United States views as a terrorist organization.

Police could not confirm whether the Tuesday incident in Bangkok has any link with the Hezbollah suspect, who is still in Thai police custody. Officers found the explosive C-4 during the search of the rented house.

U.S. State Department spokeswoman Victoria Nuland said the United States condemns the incident and offered its condolences to the victims. Even as she noted that Thai authorities were investigating the incidents, she went on to draw a parallel between Tuesday's attacks in Bangkok and Monday's attacks against Israeli diplomats in India and Georgia, both of which are also under investigation.

"What I would say is that, with regard to this bombing, the incidents in Delhi, incidents in Georgia, while we will await the results of the investigations, these events do come on the heels of other disrupted attacks targeted at Israel and Western interests, including an Iranian-sponsored attack in Baku, Azerbaijan, and a Hezbollah-linked attack in Bangkok, Thailand, before this.

"So they serve as a reminder that a variety of states and nonstate actors continue to view international terrorism as a legitimate foreign policy tool, which we consider reprehensible."

While Nuland said the United States is "not going to prejudge this," she added, "We're just concerned that these come on the heels of other incidences that clearly had links back to Iran."

Israeli Prime Minister Benjamin Netanyahu on Monday blamed the Georgia and India incidents on Iran, calling it "the biggest exporter of terror in the world."

"The Israeli government and her security organizations are continuing to operate together with local security services against these acts of terror," Netanyahu said. "We will continue to act in a strong way, systematically and steadfastly."

In an interview Tuesday with CNN's Piers Morgan, Israeli Vice Prime Minister Silvan Shalom said Iran has been trying to target Israeli and Jewish sites for "a few decades now."

"We knew that they are planning it, preparing it. We're in touch with local governments with a few countries in Asia and in other places and together we -- we're trying to prevent those attacks for a very long time," Shalom said.

"Unfortunately, they succeeded to do it in India and tried to do it in Georgia and Azerbaijan a few weeks ago. That's something Iran is responsible for."

Iranian Foreign Ministry spokesman Ramin Mehmanparast blamed Israel, accusing it of having bombed its own embassies in New Delhi and Tbilisi "to tarnish Iran's friendly ties with the host countries," Iran's state-run Islamic Republic News Agency said. "He brushed aside Israeli accusation on Iranian involvement in the bombing and said that Israel perpetrated the terrorist actions to launch psychological warfare against Iran," IRNA reported.

"Iran condemns terrorism in strongest term and Iran has been the victim of terrorism," Mehmanparast said.

Iran's supreme leader, Ayatollah Ali Khamenei, said this month that Iran would support any nation or group that stands up against Israel. He said Iran doesn't interfere in other nations but has aided such militant groups as Hamas and Hezbollah in conflicts with Israel in Gaza and Lebanon.

The modus operandi is not new. Last month, a mysterious explosion in Iran killed a man identified as a nuclear scientist -- the third such killing in the past two years in which someone placed a bomb on or under a scientist's car. A fourth survived an assassination attempt.

The United States and Israel oppose Iran's nuclear program, although numerous countries have expressed concern as well. Iran insists its nuclear program is for peaceful, civilian energy purposes.

Iranian officials, on state-run media, blame Israel and the United States for the killings of the scientists.

U.S. Secretary of State Hillary Clinton has denied "any United States involvement in any kind of act of violence inside Iran."

While Israel generally refuses to comment on accusations and speculation, Brig. Gen. Yoav Mordechai, a spokesman for the Israel Defense Forces, said on his Facebook page, "I have no idea who targeted the Iranian scientist but I certainly don't shed a tear."