BANGKOK (AFP) - Thailand's police chief on Friday insisted his officers are making "a lot of progress" in the hunt for the Bangkok shrine bomber despite the lack of arrests and mystery over the motive of the attackers.
Monday's blast killed 20 people, mostly Asian visitors, leaving police scrambling to find the assailants and sending shockwaves through the nation's vital tourism sector.
Speaking after a memorial for the dead at the scene of the unprecedented attack on Thailand, national police chief Somyot Poompanmoung said the bomb was an attempt to stoke fear and uncertainty in the capital.
"The aim is to discredit the government and create a climate of fear to deter tourists," he told reporters.
But he defended the handling of the case despite days of confusing and sometimes contradictory statements from senior police and junta officials.
"There's a lot of progress (in the case), but I can't disclose everything," he added.
Police are convinced the attack was planned and co-ordinated by a network. But there is still one prime suspect - a bespectacled man in a yellow T-shirt described in his arrest warrant as a foreigner.
Thailand has asked Interpol for help in finding the man, who was captured on CCTV calmly placing a backpack under a bench at the Hindu Erawan shrine minutes before the blast.
"I want to reaffirm that the bomb exploded from the backpack which was placed by the bench by the suspect," national police spokesman Prawut Thavornsiri told reporters. "But we cannot disclose the footage because it is too gruesome," he said.
It is not known if the suspect has already fled the country, while the authorities have also openly questioned whether he could be half-Thai or a Thai wearing a disguise.
With rumours swirling, Mr Prawut also denied media reports the police were hunting for a man with an Islamic name. "We don't have his (the suspect's) name... and even if I did why would I tell you?" he said.
But he has previously said they are looking to speak to a woman in a black top seen on the CCTV footage at the shrine.
Both the police and junta have at various times ruled out the possibility that a global terror network carried out Monday's bombing, but have later appeared to backtrack or add caveats to their comments.
Mr Somyot also played down his earlier comments that the attack on a Hindu shrine in a tourist zone of the capital was carefully planned by a network of 10 people.
Instead he said the main suspect - captured on CCTV placing a backpack under a bench at the Erawan shrine minutes before the explosion - must have had "accomplices supporting the attack".
After days of confusing and sometimes contradictory statements from senior police and junta officials, Mr Somyot also said he would restrict how often his subordinates speak to the press.
"I have instructed police not to answer questions from the media," he said.
Both the police and junta have at various times ruled out the possibility that a global terror network carried out Monday's bombing, but have later appeared to backtrack on the comments.
Internal politics, insurgents in Thailand's south, global terror networks and even private disputes have all come under the microscope as police game the likely perpetrators.
Thai media outlets had also cast suspicion on militants from China's Uighur community, a group that faces cultural and religious repression.
The Erawan shrine is enormously popular among ethnic Chinese visitors from across Asia, but the junta has said tourists from China were not the target.
Thailand has endured a decade of political unrest, but many analysts say that the choice of target and ferocity of the attack makes it highly unlikely any Thai groups with a history of violence were involved.
Meanwhile there have so far been no public links made to Muslim rebels from the country's southernmost provinces, where an insurgency has killed more than 6,400 people, mostly civilians - nor have there been any claims of responsibility.
Their fight for greater autonomy is highly localised and neither the type of bomb nor the target fits their profile.
With a bomber on the loose and a capital city on edge, pressure is building on the police.
"One or two weeks from now if there is still no answer then there will be problem... the police could hit a dead end," a senior security source told AFP, requesting anonymity.
Thai authorities issued an arrest warrant stating the prime suspect is a foreigner, after CCTV footage caught him nonchalantly walking away from the shrine moments before the blast.
Two other suspects - a Thai man visiting the shrine and his Chinese friend - who attracted suspicion after being seen on security camera footage near the main suspect were ruled out as accomplices on Thursday.
Bangkok on Friday remembered the dead after a week which has brought shock and dread. A multi-faith memorial near the shrine Friday drew together religious leaders from Thailand's Buddhist, Muslim, Christian, Hindu and Sikh communities.
Catholic cleric Monsigneur Andrew Wissanu Thanya-Anan urged unity in the face of the attack on the hugely popular Hindu shrine, which is also a place of worship for the kingdom's majority Buddhist population.
"Even dogs have ethics when they fight. Not these people (the attackers). It has caused terrible hurt to all Thai people, all religions," he told AFP.
Doves were also released at the shrine on Friday.
Thailand has asked Interpol for help in finding the main suspect, a young bespectacled man in a yellow t-shirt who authorities have speculated may have been wearing a disguise.
A police spokesman late Thursday hinted that investigators are looking at whether a private dispute could be behind the blast, but refused to give further details.
Thai authorities issued an arrest warrant stating the prime suspect is a foreigner, after CCTV footage caught him nonchalantly walking away from the shrine moments before the blast, and have said they are not sure if he has already fled the kingdom.
Two other suspects who attracted suspicion after being seen on security camera footage near the main suspect at the shrine were ruled out as accomplices on Thursday.
Police said they were a Thai man who was visiting the shrine with his Chinese friend, and handed himself in to police once the pair were identified as potential suspects. He has since been cleared, along with the Chinese man who returned home a day after the blast.