Friday in which four people were killed and 30 others wounded, according to Thai media.
religions among ethnic minorities or was under threats linked to Islamic State (IS) terrorism.
Authorities were also looking into whether fires in Nakhon Si Thammarat and Surat Thani were linked to the blasts or not.
some suspects have been detained for questioning, said Pol Maj Gen Piyaphan.
two men were being questionined for suspected involvement in the explosions on Thursday night and Friday morning.
a suspicious bag has been discovered outside a bank.
The area has been sealed off and explosive ordnance disposal (EOD) officers are said to be on the way.
the site told a Channel 8 reporter that altogether 6 explosive devices have been discovered although there are rumours of many more.
a third was rendered safe, injuring one person.
A motorcycle taxi driver was slightly injured.