CRI听力:Two Suspects Cleared by Police after Questioning over Bangkok Attack

A Chinese tourist and his Thai guide who were earlier identified as possible accomplices in the Bangkok bombing have been cleared by Thai Police after questioning.

They were caught on security cameras standing in front the prime suspect just minutes before Monday's blast at the popular Erawan Shrine.

But Thai police spokesperson Prawut Thavornsiri says the two men, who turned themselves in after seeing their pictures in the media, are not involved.

"The man in a red t-shirt met with police at the Lumpini police station, and then was investigated at the Investigation Centre in Phayathai. Now police have already finished investigating him, and he has been released. The man in the white t-shirt, who is Chinese, already went home to China yesterday. For our preliminary investigation, they are not involved."

The main suspect - thought to be "a foreign national" - remains at large.

But authorities say they believe he is still in Thailand.

The name and nationality of the man seen in a yellow t-shirt - leaving a backpack at the shrine just three minutes before the blast - has not yet been established.

Police are now questioning a tuk-tuk driver who drove him to the shrine.

"The suspect and tuk-tuk driver couldn't communicate. They communicated by a photograph shown on the suspect's phone."

New CCTV footage shows the main suspect on a motorbike taxi, heading south, towards one of the largest public parks in downtown Bangkok, just minutes after the blast.

The motorbike driver says he dropped off the suspect near the Lumpini park.

Police say they have lost all trace of him since then.

Thai Police now say that at least 10 people are suspected of being involved in the deadly attack that killed 20 people, mostly foreigners, and injured more than 120.

Officials say they believe the attack was planned at least a month in advance.

However, Thai military spokesperson Colonel Winthai Suvaree says it was "unlikely" that the attack was the work of an international terror group.

He also adds the attack did not specifically target Chinese tourists.

"The security services have received cooperation from allied countries, and we have the same opinion - that at the moment, the incident was unlikely to have been the work of an international terrorist group, and we think the group was not directly targeting Chinese tourists, because there were other nationalities affected too."

Bangkok remains on high alert.

Police have deployed an extra 10,000 personnel on the ground in the wake of the deadliest attack in the city's recent history.

For Cri I'm Poornima Weerasekara.