Indonesian authorities uncovered a terrorist plot to attack the U.S. Embassy in Jakarta, among other targets, as they arrested 11 suspects in raids Friday and Saturday.

The suspects are affiliated with a new militant Islamist group called the Harakah Sunni for Indonesian Society, or Hasmi, according to Maj. Gen. Suhardi Alius, a representive of the national police, the Associated Press reported.

Alius said Hasmi also planned attacks on the U.S. Consulate in Surabaya, the offices of the U.S. mining company Freeport-McMoran Copper & Gold Inc. in Jakarta, a public plaza near the Australian Embassy in Jakarta, and the headquarters of a special police forces in central Java.

"From evidence found at the scene, we believe that this group was well prepared for serious terror attacks," AP quoted Alius as saying.

Police found bomb-making instructions and homemade explosives during the raids that took place in four different provinces.

Authorities are currently investigating whether Hasmi has ties with Indonesia’s larger terrorist organizations, such as Jemaah Islamiyah.

Indonesia has been cracking down on terrorist groups since the deadly 2002 bombings in Bali that are believed to have been carried out by Jemaah Islamiyah and killed 202 people, most of them foreigners on vacation.

As law-enforcement pressure increases on large groups like Jemaah Islamiyah, smaller groups have been popping up in Indonesia.