Jakarta – Police have arrested 17 suspected members of a radical group campaigning to establish an Islamic state within Indonesia, reports said Tuesday.

The detainees, arrested at a house in West Java on Monday, said they had surrendered their Indonesian citizenship and taken an oath to become members of Negara Islam Indonesia Region-9 (NII KW-9), senior West Java police officer Irianto told the Jakarta Post.

"Some residents living close to the house were suspicious of people staying there and their guests. With the residents' tip-off we spied on them and later raided the house," Irianto was quoted as saying by the daily.

The detainees had also told police that they were each required to recruit six to 10 new members, Irianto said.

Police confiscated documents on NII's history, vision and mission from the house in Bandung. It was not immediately clear what law the suspects were being detained under.

The NII is the subject of investigations by police and the country's highest Islamic authority as to whether it is linked to an Islamic boarding school in the West Java town of Indramayu.

Indonesia Council of Ulemas (scholars) deputy chairman Umar Shihab told AFP last week that it would "never tolerate the existence of the NII" and would demand the closure of the Al-Zaitun school if it "is proven to be a tool of the NII." Parents of students accuse the school of teaching a deviant form of Islam.

Monday's arrests in Bandung are the second of alleged NII members in the mountain city. In January ten people were arrested but only one was held as a suspect while nine were released.

NII followers say they are the new generation of a group called Darul Islam, whose leader Sekarmaji Marijan Kartosuwiryo proclaimed the establishment of an "Indonesian Islamic State" in 1949.

Kartosuwiroyo was executed by the government of then-president Sukarno in 1962 after several bloody rebellions on Java, Sumatra and Sulawesi.

Another seven people were arrested Monday in Bandar Lampung city in southern Sumatra on suspicion of belonging to the Darul Islam, the Post reported.

Indonesia is the world's largest Muslim-populated nation but Islam is not the state religion and most people practise a moderate form.

The NII says people who do not subscribe to its belief that Indonesia should be ruled by Islamic law are non-believers.