JAKARTA (Reuters) - President Joko Widodo said on Wednesday that authorities would "clobber" any group threatening to destroy Indonesia's tradition of pluralism and moderate Islam, and called for unity ahead of presidential elections in 2019.
Religious and political tensions have spiralled in the last six months with Islamist-led rallies against Jakarta's former governor, Basuki Tjahaja Purnama, an ethnic Chinese Christian who was charged with insulting the Koran and put on trial.
Hardline Islamist groups, banned under the authoritarian regime of president Suharto, which ended in 1998, have gained ground in recent years, though they are usually small and on the fringes of society.
In an interview with Metro TV, Widodo said there were no words other than "clobber" or "kick" to describe how to deal with groups that threatened the stability of the state.
"Because it is very fundamental: Pancasila, a united Republic of Indonesia, the 1945 constitution, 'Unity in Diversity'. If anybody tries to change these, shift these, there are no other words."
Indonesia is the world's biggest Muslim-majority country, but its state ideology, Pancasila, includes national unity, social justice and democracy alongside belief in God, and enshrines religious diversity in an officially secular system of government.
Widodo declined to single out any groups but this month officials said that Hizb ut-Tahrir Indonesia (HTI), an Islamist group that calls for a state based on sharia law, would be disbanded because it wanted to undermine the secular system.
HTI has urged the government not to disband it, saying every citizen has a right to organise and deliver Islamic teaching.
Another such group, the Islamic Defenders' Forum (FPI), rose to prominence during the recent Jakarta elections. The group was instrumental in mobilising hundreds of thousands of Muslims to rally against Purnama, who is an ally of Widodo.
Purnama was sentenced this month to two years in jail, far longer than the penalty asked for by the prosecution. The sentence was condemned by critics as unfair and politically motivated.
He denied the blasphemy charges but his trial affected his popularity and he was ousted as Jakarta governor in a run-off against a Muslim rival in April.
The election was widely seen as a proxy battle for the presidential election in 2019, and Widodo said that, while it was normal for the political temperature to rise, the contest should not divide society.
"We must stay in the existing corridor and, once again, don't take society into a social rift, which makes us disharmonious, or makes us become disunited," he said.
Reporting by Fransiska Nangoy, Nilufar Rizki and Fergus Jensen; Writing by Ed Davies; Editing by Kevin Liffey