Jakarta – Tension between Indonesia's two main Muslim organizations heightened Wednesday with thousands of supporters of President Abdurrahman Wahid threatening their rivals with violence if its chairman seeks to unseat the president in mid-term.

Thousands of Muslims led by 17 young religious leaders affiliated with the Nahdlatul Ulama (NU), Indonesia's largest Muslim organization, packed the main avenue of Pasuruan in East Java to express support for Wahid, police there said.

"There was no incident, it was only a show of support for Gus Dur [Wahid's popular appelation]," an officer on duty at the Pasuruan district police who only identified himself as Siswanto told AFP by telephone.

Siswanto said police estimated the number of ralliers at a bit above 3,000 while several television stations put the number closer to 10,000. Pasuruan is a stronghold of the 30-million-strong NU, a traditionalist Muslim movement which counts Wahid as one of its former chairmen.

"If Gus Dur and Mega go down, Muhammadiyah will be destroyed," a poster carried by one of the supporters said, referring to Wahid and Vice President Megawati Sukarnoputri.

Muhammadiyah, which claims up to 28 million members, is Indonesia's second largest Islamic organization and counts national assembly chairman and Wahid critic Amien Rais as one of its former chairmen.

Orators during the pro-Wahid rally made virulent attacks on Rais and Muhammadiyah, accusing Rais betraying reform and democracy, private ANTv television said. One of the religious leaders even said it would be religiously acceptable to draw Rais' blood if he succeeded in deposing Wahid in mid-term, ANTv said.

Rais, who has presidential ambitions, has been at the forefront of efforts by some politicians to demand Wahid resign because of alleged incompetence and corruption. Wahid's detractors claim he has failed to revive the economy or tackle violent separatist conflicts.