Thai police yesterday found four M67 grenades inside a parcel that was returned to a private courier service shop in Bangkok's Bang Khen district, the latest in a series of security incidents in the Thai capital.
Staff members of the Kerry Express office alerted the police after they found suspicious-looking objects inside an unclaimed parcel.
Police dispatched an Explosive Ordnance Disposal team to the shop and found the grenades wrapped in black plastic tape inside the box. The grenades were "live" and had a kill zone of 5m and casualty radius of up to 15m.
The package was addressed to someone named "Mac" at a house in Phanat Nikhom district, Chon Buri province, about 80km from Bangkok. The recipient could not be located so the package was returned to the sender, a certain "Issapong Prombutr" who did not specify a forwarding address and had given only a mobile phone number.
Ms Ratchaneekorn Rucheeprat, a Kerry Express employee, said the parcel was sent on May 6 from the shop and was returned after seven days. She said workers decided to open the package when they were clearing unclaimed parcels.
Police said they will locate and call in the sender for questioning.
The incident comes two days after a pipe bomb was found in an overgrown lot behind the Thailand Cultural Centre subway station.
The pipe bomb, measuring 20.3cm long and 7.6cm wide, was packed with 220g of low-pressure explosives and found inside a basket together with an assortment of cut metal, screws and nails.
The package was addressed to someone named "Mac" at a house in Phanat Nikhom district, Chon Buri province, about 80km from Bangkok. The recipient could not be located so the package was returned to the sender, a certain "Issapong Prombutr".
It had a casualty radius of between 10m and 20m.
The National Council for Peace and Order earlier dismissed any links between the recovered pipe bomb and recent bombings in the capital.
Three pipe bombs have exploded in different areas of Bangkok over the last two months: in front of the Government Lottery Office on April 5, in front of the National Theatre on May 15, and inside the VIP waiting room of the military- owned Phramongkutklao Hospital on May 22.
The first two blasts were minor and did not cause serious damage but the hospital bombing injured 25 people.
The authorities have tightened security in the city, particularly at airports, and train and subway stations after the hospital attack.
Investigators have given different information on who they suspect are behind the incidents, variously pointing fingers at Muslim insurgents in southern Thailand and political activists disgruntled with the military government, prompting criticism of their lack of cohesion.