Indonesian police on Monday said the four foreigners arrested over the weekend suspected of being linked to the Islamic State jihadist group were from China's ethnic Uighur minority.

A day after identifying the four men as Turks, police said they had investigated and found that they had entered Indonesia using forged Turkish passports.

The elite Detachment 88 police squad had arrested them, along with three Indonesians, after tailing their car on Saturday in the central Sulawesi district of Poso, a known hotbed for militant activity.

"It turned out that the four foreigners arrested were Uighurs, after investigation by the anti-terror police," national police spokesman Ronny Sompie told reporters.

"They had used fake passports," he added.

The men had paid $1,000 to a broker in Thailand for each passport and used them to enter Malaysia and Indonesia, Sompie said.

Agus Rianto, another police spokesman, said the men were being investigated for alleged connections with the Islamic State jihadist group.

National police chief Sutarman said they wanted to meet Santoso, the leader of a group called the Eastern Indonesia Mujahideen that hides out in the jungles around Poso.

"We are still investigating why they wanted to meet Santoso, whether for training or for terror acts," he added.

Indonesia is home to the world's biggest Muslim population of about 225 million and has long struggled with terrorism. But a successful clampdown in recent years has seen the end of major deadly attacks.

Jakarta has estimated that dozens of Indonesians have travelled to Syria and Iraq to fight and President Susilo Bambang Yudhoyono said he was concerned about their return, adding that he had tasked agencies to oppose the spread of extremist ideology in the sprawling nation.