Police in Thailand said Monday that they had charged a Lebanese man suspected of planning an attack in Bangkok, after potentially explosive materials were found near the capital.

The man was charged with violating weapons control law, deputy national police chief Pansiri Prapawat said, after a large amount of fertiliser and ammonium nitrate was found at a property rented by the suspect.

Ammonium nitrate is commonly used in agriculture, but mixed with other substances can make a bomb. Possession of the chemical requires a permit in Thailand.

Thai authorities allege the man, who was detained on Thursday, has links to Hezbollah, an Iranian- and Syrian-backed Muslim Shiite group that is blacklisted as a terrorist organisation by Washington.

According to police, the suspect said the property had been rented for two years and was used to store goods that were then sent to the Middle East.

Police said Saturday the suspect had admitted during interrogation that a group was planning an attack in Thailand, but that the plot had been called off.

Thai authorities have repeatedly played down the risk and withheld information about the possible plot until after the United States warned Friday of a terrorist threat against tourists in the kingdom.

"Foreign terrorists may be currently looking to conduct attacks against tourist areas in Bangkok in the near future," the US embassy in Bangkok said in an emergency message posted on its website.