Bangkok  - Thailand's army chief, General Anupong Paojinda, admitted Thursday that bullets used in last week's assassination attempt on media mongol Sondhi Limthingkul came from a military arsenal used for shooting practice.

Unidentified gunmen on April 17 riddled the car of Sondhi, a core leader of protests that shut down Bangkok's two airports last year, with more than 100 bullets from AK-47, M16 and HK33 assault rifles.

Sondhi survived the attack with minor head injuries from bullet fragments.

M16 cartridges found at the scene of the attack have been traced to the army's 9th Infantry Division, Anupong acknowledged, adding, "I already ordered an urgent investigation into the matter."

The army chief previously speculated that the assassination attempt was a "criminal matter."

Sondhi was one of the top leaders of the Peple's Alliance for Democracy (PAD), which held six months of protests in Bangkok last year, culminating in the closure of Bangkok's two airports and the downfall of the previous government that was openly supportive of ousted premier Thaksin Shinawatra.

Sondhi co-founded the PAD in early 2006 as a mass movement dedicated to the overthrow of then-prime minister Thaksin, who was toppled by a coup on September that year.

Last year's street protests were against a government led by the People Power Party, which was dissolved by the Constitution Court for election fraud in December, paving the way for a new cabinet led by Thaksin's political foes.

Speculation about who was behind the assassination bid on Sondhi has been rife.

Thai Foreign Minister Kasit Piromya on Wednesday reportedly told the Asia Society in New York that Thaksin was behind the attack.

Several Thai newspapers have speculated that the botched assassination on Sondhi must have been carried out by military men although apparently ones who had not excelled at target practice. (dpa)