Israel has accused arch-enemies Iran and its Lebanese ally Hezbollah of being behind twin bomb attacks that targeted embassy staff in India and Georgia, wounding four people.
Tehran denied involvement in the strike, which has amplified tensions between two countries at loggerheads over Iran's contested nuclear programme.
Hezbollah, the powerful Shi'ite Muslim movement in neighbouring Lebanon, declined to comment.
Police in the Indian capital New Delhi said a bomb wrecked a car carrying the wife of the Israeli defence attache as she was going to pick up her children from school.
She needed surgery to remove shrapnel but her life was not in danger, officials said.
Three others suffered lesser injuries in the same blast.
Israeli officials said an attempt to bomb an embassy car in the Georgian capital Tbilisi had failed and the device was defused.
Israel had put its foreign missions on high alert ahead of the anniversary of the 12 February 2008 assassination in Syria of the military mastermind of Hezbollah, Imad Moughniyeh - an attack blamed on the Jewish state.
Israel is also believed to be locked in a wider covert war with Iran, whose nuclear programme has been beset by sabotage, including the unclaimed killings of several Iranian nuclear scientists, most recently in January.
Prime Minister Benjamin Netanyahu was quick to blame both Iran and Hezbollah, accusing them of responsibility for a string of recent attempted attacks in countries as far apart as Thailand and Azerbaijan.
"Iran and its proxy Hezbollah are behind each of these attacks," said Mr Netanyahu.
"We will continue to take strong and systematic, yet patient, action against the international terrorism that originates in Iran."
Iran's ambassador to India denied that his government had anything to do with the attack on the New Delhi embassy.
"Any terrorist attack is condemned (by Iran) and we strongly reject the untrue comments by an Israeli official," Mehdi Nabizadeh was quoted as saying by IRNA.
"These accusations are untrue and sheer lies, like previous times."
Israeli officials have long made veiled threats to retaliate in Lebanon for any Hezbollah attack on their interests abroad, arguing that as the militia sits in the government in Beirut, its actions reflect national policy.
The New Delhi blast took place some 500 metres from the official residence of Indian Prime Minister Manmohan Singh.
BK Gupta, the New Delhi police commissioner, said an eyewitness had seen a motorcyclist stick a device to the back of the car, which had diplomatic plates.
"The eyewitness ... says it (was) some kind of magnetic device. As soon as the motorcycle moved away a good distance from the car, the car blew up and it caught fire," said Gupta.
The Iranian scientist killed in Tehran last month died in a similar such attack. No one has claimed responsibility for this.
Israel named the injured woman as Talya Yehoshua Koren.
"She was able to drag herself from the car and is now at the American hospital (in New Delhi), where two Israeli doctors are treating her," said a defence ministry spokesman.
Thailand said last month its police had arrested a Lebanese man linked to Hezbollah and he later led them to a warehouse stocked with bomb-making materials.
Also last month, authorities in Azerbaijan arrested two people suspected of plotting to attack Israel's ambassador and a local rabbi.
In a 24 January speech, Israel's military chief of staff, Lieutenant-General Benny Gantz, accused Hezbollah of trying to carry out proxy attacks while avoiding direct confrontation.
Israel and Hezbollah fought an inconclusive and costly war in 2006.
"During this period of time, when our enemies in the north avoid carrying out attacks, fearing a harsh response, we are witnesses to the ongoing attempts by Hezbollah and other hostile entities to execute vicious terror attacks at locations far away from the state of Israel," Mr Gantz said.
"I suggest that no one test our resolve."