BANGKOK (Reuters) - Thailand's police chief said on Thursday (Aug 20) at least 10 people were suspected of involvement in a bomb attack in Bangkok this week that killed 20 people, more than half of them foreigners.

Earlier, the police said they believed at least three people, including a foreign man, were involved in the attack on a famous city shrine.

"It is a big network. There was preparation using many people," police chief Somyot Poompanmuang told reporters.

"This includes those who looked out on the streets, prepared the bomb and those at the site and... those who knew the escape route," he said. "There must have been at least 10 people involved."

However, the ruling junta said that the attack was "unlikely" to be the work of international terrorists, adding that it was not specifically targeted at Chinese tourists.

"Security agencies have cooperated with agencies from allied countries and have come to the preliminary conclusion that the incident is unlikely to be linked to international terrorism," said Colonel Winthai Suvaree, a spokesman for the junta, known as the National Council for Peace and Order.

The site of the blast, the Erawan Shrine, is popular with Chinese tourists.