Bangkok: Thai police on Sunday deployed personnel and sniffer dogs to check major tourist destinations here as authorities continued looking for the suspect involved in last Monday's bombing at the Brahma temple during rush-hour that killed 20 people.
Local media quoting unnamed sources said investigators believed that the blast plotters may have relied on a foreign bomb-making technique.
Security was beefed up at several important tourist spots, with personnel and sniffer dogs monitoring the areas.
The shrine attack occurred on Monday night and the pier attack occurred on Tuesday afternoon.
While the shrine blast killed 20 people and injured more than 100 others, the bomb at the pier exploded in a canal causing no injuries.
According to the source, TNT was used for both pipe bombs.
More evidence have been obtained which may be related to the two blasts but no further details were given.
Police have also considered the possibility that the pier blast might have been unintentional as the person who discarded the bomb in the water might have just wanted to get rid of the explosives.
They said 56 of the shrine blast victims remained hospitalised.
There have been no arrests so far. The hunt has been focused on a suspect in a yellow T-shirt seen on CCTV placing a rucksack under a bench at the Erawan shrine minutes before the blast.
A sketch has been widely circulated of the man who has been described in his arrest warrant as "foreign" though a military spokesman said a connection to international terrorism was unlikely.
Little headway has been made in tracing down the main suspect nearly a week after the blast but the national police chief Somyot Poompanmoungyot told reporters today it was not a lack of their capacity but a lack of modern equipment that has been hampering investigations.
Though he did not specifically mention what equipment the police need, he might be referring to programmes to enhance CCTV footage or facial recognition technology.
Yesterday, police examined new CCTV footage showing an unidentified man dropping a package into the canal where the second explosion took place.