Thai police say at least 10 people were involved in Monday's Bangkok bomb attack.
They also say that it had been planned at least a month in advance.
The country's top officers told reporters the large network included those who kept look-out, people who prepared the bomb and those who planted it.
The bombing of a Bangkok shrine that killed at least 20 people was “unlikely to be linked to international terrorism”, Thailand’s military junta spokesman Colonel Winthai Suvaree said.
He also said that Chinese tourists, who were among the victims, were not the “direct target”.
“The security agencies have collaborated with intelligence agencies from a lot of countries and have come to the same preliminary conclusion that the incident is unlikely to be linked to international terrorism,” he said.
More than 120 people injured in Monday evening’s blast at Erawan Shrine, a popular tourist site that is known to attract Chinese visitors.
On Tuesday, police issued an arrest warrant for the prime suspect, describing him as an unidentified “foreign” man.