Thailand and Malaysia agreed to strengthen cooperation in checking cross-border passengers following blasts in Thailand's southern border provinces of Yala and Songkhla on Saturday.
Foreign Minister Surapong Tovichakchaikul said Prime Minister Yingluck Shinawatra and her Malaysian counterpart Najib Razak agreed to increase vigilance in checking people and vehicles crossing the Thai-Malaysian border, at the Association of Southeast Asian Nations (Asean) summit in Phnom Penh.
It has been reported that rebels have taken shelter across the Malaysian border after committing violent acts in Thailand.
Foreign Ministry spokesman Thani Thongphakdi said Ms Yingluck also told Asean leaders the government would take care of those injured in the Saturday bombings and would bring those behind the attacks to justice.
In one of the attacks, Malaysian tourist Low Tsian Hock was killed and several Malaysians injured by a car bomb at the Lee Gardens Plaza Hotel in Hat Yai.
Asean also condemned the bombings and expressed hope the situation would improve before long.
"The Malaysian and Thai prime ministers held unofficial talks on this issue and Asean hopes things will return to normal soon," Surin Pitsuwan, the outgoing secretary-general of Asean, said.
Her Majesty the Queen donated gift sets to victims of the car bombs in Yala and Songkhla yesterday.
Thai Red Cross secretary-general Phan Wannamethee gave royally donated gift sets to injured people being treated in hospitals in Yala and Songkhla on behalf of the Queen.
Yala deputy governor Prayoon Rattanasenee said authorities have obtained several important clues, including security footage which captured images of the suspected vehicles.
The footage shows an Isuzu pickup truck and a Toyota pickup truck used by suspected insurgents entering and leaving an Islamic school.
The vehicles also entered a mosque in front of the school, Mr Prayoon said.
In Pattani yesterday, police arrested a suspect allegedly involved in one of Saturday's bomb attacks, at a restaurant in front of Mae Lan district police station.
The suspect was identified as Samlee Huluduerae.
He denied being involved in the attacks.