The sticky bomb used in the terror attack on the Israeli embassy car was used for the first time in India and could have been made by foreign experts, a senior police official said.

Delhi Police Commissioner B.K. Gupta said a sophisticated incendiary palm-size device was used in the blast, a first of its kind in a terror attack in India.

"This has been giving officials cause for concern that the bomb was perfectly made and we have never seen such a bomb in Delhi. Maybe, it was made by foreign experts," said Gupta.

Gupta further said it is premature to say who planted or made the bomb.

Sources involved in the investigation said that sticky bombs and silencer-fitted weapons are the latest tactics being adopted by insurgents in Baghdad and other places.

Sometimes there are several such attacks a day, usually targeting government or security officials with pinpoint accuracy.

The official added that by sticking a small bomb under a vehicle or using a silencer-fitted weapon, the attackers can operate quickly and without drawing much attention to themselves.