Police in Thailand are investigating a grenade attack in Bangkok early Wednesday at a building housing the offices of Israeli national airline, El Al. There were no injuries from the attack, which police say may not have been aimed at the airline.

The blast from a rocket-propelled grenade occurred early in the morning in central Bangkok. It caused minor damage to the facade of a 15-story office building that houses the Israeli national airline's offices. But police and the Israeli ambassador say it is not clear that El Al was the target.

Lieutenant General Anan Piromkaew, the chief of Bangkok's metropolitan police, says the grenade was meant as a threat and was probably directed at the Lotus Tesco supermarket nearby.

British company Tesco owns several supermarkets in Thailand in a joint venture with a Thai company. The stores have been hit by a series of bombings recently because of a dispute with the company's security contractors.

General Anan says an abandoned anti-tank M-72 grenade launcher was found in a small lane near the building amid shattered glass and masonry.

No one was injured in the attack. The area was nearly empty because of a Thai national holiday.