JAKARTA, Indonesia (CNN) -- Indonesian police have arrested 12 suspected militants who were planning to attack an area frequented by tourists, authorities said Thursday.
The arrests foiled a plot to bomb a cafe in Bukittinggi, a city in West Sumatra that's popular with tourists, said police spokesman Abubakar Nathaprawira.
Authorities also seized a large cache of explosives, including bomb-making materials and guns, Nathaprawira said. The bombs that were being constructed were highly sophisticated, police sources said.
Police arrested the suspects -- which include three foreign nationals -- in Palembang, a city on the island of Sumatra, the sources said.
Masked and heavily armed plainclothes police officers transferred the men -- handcuffed and wearing balaclavas, or ski masks -- from a plane onto police buses at an airport in the capital city of Jakarta.
Nathaprawira said one of the men is an English teacher and bomb-making expert who is an associate of Mas Selamat Kastari, a leader with the Islamic militant group Jemaah Islamiyah. Kastari escaped from a Singapore detention center in March.
Some of the other suspects are members of a group associated with Noordin Mohammad Top -- a one-time officer, recruiter and bomb-maker for Jemaah Islamiyah, the police spokesman said.
Indonesia has been battling the al Qaeda-linked Jemaah Islamiyah, which aims to create a Muslim "superstate" across much of Southeast Asia. Authorities blame the group for the Bali nightclub bombings of 2002, which killed more than 200 mostly Western tourists.
The group is also suspected of subsequent attacks on the Australian Embassy and J.W. Marriott hotel, both in Jakarta.
CNN's Kathy Quiano contributed to this report.