A hitman on a motorbike fixed a suspected magnetic bomb on an Israeli embassy car in the Indian capital on Monday, police said, in one of two attacks in New Delhi and Tbilisi blamed by Israel on Iran.

The embassy car exploded in a ball of flames in a diplomatic area of central New Delhi, injuring a 42-year-old female diplomat and her Indian driver who were pulled from the wreckage by bystanders, according to witnesses.

In the Georgian capital Tbilisi, 2,300 miles (3,700 kilometres) to the west, an embassy employee found a suspicious device in his car and contacted police who were able to defuse the bomb before it went off.

"Iran is behind these attacks. It is the biggest exporter of terror in the world," Israeli Prime Minister Prime Minister Benjamin Netanayhu told members of his right-wing Likud party in Jerusalem.

The Israeli leader said there had been a number of attempts to harm Israelis and Jews in recent months in places such as Thailand and Azerbaijan in a series of plots coordinated by Tehran and Lebanon's Shiite militia Hezbollah.

Iranian foreign ministry spokesman Ramin Mehmanparast was quoted by Al-Alam television as "categorically" rejecting the accusations. "Iran condemns all acts of terrorism," he said.

In New Delhi, police commissioner B.K. Gupta said that a witness had seen a man ride up behind the targeted vehicle -- a silver Toyota with diplomatic plates -- as it approached a junction shortly after leaving the Israeli embassy.

"He saw a man on a motorbike sticking some kind of a device on the rear side of the car," the police commissioner told reporters. "Just a few seconds after the car exploded."

The 42-year-old diplomat inside -- the wife of the defence attache in New Delhi who was on her way to collect her children from school -- was taken to a private hospital where she was said to be critical but stable.

Her driver and two others were also injured.

"She is in the OT (operating theatre) for spine surgery," medical superintendent of Primus Hospital, N.D. Khurana, told AFP. "There are so many injuries... She is critical but she is stable."

Am Israeli defence minstry spokesman in Jerusalem named the woman as Tal Yehoshua Koren and said she was on her way from the embassy to her children's school at the time of the attack.

"She is being operated on and will be flown back to Israel as soon as possible," the spokesman told AFP.

Witnesses heard an explosion around 3:30 pm (1000 GMT) and described a blast of relatively low intensity.

The charred remains of the car surrounded by debris stood in the street until the early evening, with the roof still intact but the back door missing.

"I was opposite when the explosion occurred. All of a sudden there was a boom and I saw that a car was engulfed in fire. I really got a shock," witness Shashwati Goswami, a New Delhi communications lecturer, told AFP.

The wounded driver Manoj Sharma told the Press Trust of India that he had washed the car that morning and had already run several errands before the blast struck.

"I just felt the fire and I came out... and then brought out madam. I then put her inside a three-wheeler (auto) and went with her to the embassy," a stunned Sharma was quoted as saying from hospital.

The method used in the attacks closely mirrors the tactics of assassins that have been targeting Iranian nuclear scientists with magnetic bombs placed on their cars.

Three scientists and a physicist have been killed in the last two years in murders blamed by Iran on Israeli and American secret services.

The bomb plots in New Delhi and Tbilisi also fell between anniversaries of the deaths of two top militants from Hezbollah, the militant group which has close ties to Iran. The anniversary sparks annual travel warnings from Israel.

The Indian government ordered the tightening of security at diplomatic missions, while Foreign Minister S.M. Krishna voiced regret.

"India very strongly condemns such incidents and it is going to be fully investigated and the culprits will be brought to justice at the earliest," he said in a statement.

In Washington, US Secretary of State Hillary Clinton condemned the "cowardly" attacks in the "strongest possible terms" and offered US help with investigations.

Israeli Foreign Minister Avigdor Lieberman said the attacks proved that Israelis both at home and abroad were "a target for terrorists" but that the country knew "how to identify those who are responsible."

The last militant strike in New Delhi was in September when a bomb outside the High Court killed 14 people -- the latest in a series of blasts that has shaken public confidence in the Indian government's counter-terror capabilities.

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