As the covert war between Iran and Israel moves into the open, the Jewish state is looking to use the attacks in Thailand and India to up diplomatic pressure on Tehran's nuclear bid, commentators say.

Tensions have risen sharply following three bomb incidents in world capitals in less than 24 hours, putting the spotlight firmly on the ongoing shadow war between played out between the two foes over Tehran's contested nuclear programme.

Israel has blamed Iran for a series of bomb attempts targeting Israeli embassy personnel in India and Georgia, and another botched attempt in Thailand, accusing Tehran of staging a coordinated campaign of attacks against its diplomats.

Thai police have charged two Iranians over an alleged anti-Israeli bomb plot, with a senior intelligence official telling AFP they were "an assassination team and their targets were Israeli diplomats, including the ambassador."

Their plan, he said, was "to attach bombs to diplomats' cars."

A third Iranian suspect was later arrested in Malaysia, police said.

"Iran's terrorist activities have been exposed to everyone," Israeli Prime Minister Benjamin Netanyahu said on Wednesday, accusing the Islamic republic of "harming innocent diplomats across the world."

Iran has denied any connection with the attacks but Mickey Segal, a former Iran desk chief at Israel's Mossad spy agency, said the perpetrators must have had the go-ahead from Iran's supreme leader Ayatollah Ali Khamenei.

"You don't carry out attacks like that without direct instructions from Khamenei," he told AFP.

Many commentators said the attacks appeared to be an attempt to avenge the assassination of four Iranian scientists, which Iran blamed on Israel.

"The professional level of the perpetrators of the terror attacks was not high, but the events show great audacity and willingness to establish a balance of deterrence that would prevent attacks on Iranian nuclear scientists," the top-selling Yediot Aharonot said.

Observers were quick to point out that the modus operandi used by the bombers in Delhi -- motorbike assassins using a magnetic bomb to hit the target's car -- was almost identical to that used in the killings of three of the Iranian scientists, the latest of which took place on January 11.

"We will never forego punishing the perpetrators of this crime and those behind the scenes responsible for it," Khamenei said at the time, pointing the finger at the Mossad.

According to Boaz Ganor, an Israeli expert in counter terrorism at the Herzliya Interdisciplinary Centre, the use of magnetic bombs was a clear message from Iran.

"We believe Tehran is behind these recent attacks because the MO used in New Delhi and Tbilisi is that same as that used in the recent assassinations of Iranian scientists: a magnetic object attached to the back of a car," he told AFP.

"That is a way of Iran putting its signature on the attacks and in that way, sending a message aimed at deterring Israel," he said.

With the covert war forced into the open, Israel was likely to use the attacks to increase global pressure on Iran and its nuclear programme, which much of the West believes is a drive to obtain nuclear weapons.

Iran denies that.

"The Israeli-Iranian war has now moved out of the shadows," wrote commentator Yaakov Katz in The Jerusalem Post.

"As long as the attacks are not successful, Israel is going to try and use the spate of attacks to its benefit, and specifically garner international support against Irans nuclear programme," he wrote.

"Israeli intelligence agencies are now working to try and connect the dots among the three recent terror plots ... in an effort to be able to portray Iran as what Israel claims it is: the greatest state sponsor of terrorism in the world."

The goal, he said, was to convince the world to impose tougher sanctions on Tehran and to stress the dangers of allowing such a regime to obtain nuclear arms.

The Israel HaYom free sheet took a similar line.

"Israeli officials hope to be able to use the events of the past number of days ... to gain leverage that might allow for an even tighter blockade to be imposed on Iran over its nuclear programme," the paper said.

The former Mossad official said the attacks would definitely strengthen Israel's hand in the diplomatic offensive against Iran.

"All these things help the strategic environment which is building up against Iran as a terror-supporting state," said Segal, now a senior analyst at intelligence analysis firm, Terrorgence.

"Obviously if you catch a person with an Iranian passport, it greatly helps the Israeli-Western narrative against Iran."