Two persons of interest in Monday' s deadly bombing attack have been questioned by Thai police and then cleared of involvement, local media reported Friday.

Earlier, police saw in security camera footage two males, dressed in red and white respectively, were standing close to a main suspect, against whom an arrest warrant has been issued, prior to the explosion that killed at least 20 people and injured more than 100 others.

Khaosod English quoted a police source as saying that the two reported to the police for questioning on Thursday.

They were released after investigators determined they were not involved, the source said.

No individual or group has yet claimed responsibility for the blast that rocked Erawan Shrine at Ratchaprasong intersection in downtown Bangkok on Monday night.