A Thai television station is reporting that a Lebanese suspect with alleged links to Hezbollah militants has led police to a warehouse housing materials that could be used to make explosives.
Thai PBS television showed police confiscating boxes of urea fertiliser and liquid ammonium nitrate in the raid.
The raid comes after the US and Israel warned of a terror threat targeting their citizens in Bangkok. Officials say that threat has now been thwarted.
The Lebanese suspect was detained on Thursday. He led police to the warehouse, where police also found three beds, matching accounts that the man was travelling with two companions.
The terror alert came amid growing tensions over US and Israeli responses to Iran's nuclear programme.