As the country's largest Islamic organization celebrated its 85th anniversary on Sunday, religious and national leaders vowed to tackle the rising tide of Islamic radicalization and to keep religion out of politics.

In a speech before thousands of Nahdlatul Ulama faithful at Bung Karno Stadium, NU chairman Said Aqil Siradj said the group had a key role to play in preventing radicalization.

The organization, he said, was founded to promote an interpretation of Islam that could benefit the people, "not an Islam that was radical, extreme or terrorist". "NU is characterized by moderation, balance and tolerance," he said.

The organization in no way condoned recently uncovered attempts to turn Indonesia into an Islamic state, he added. "Indonesia is not a country based on religion or ethnicity, but a secular nation."

Said Aqil also said the group would not get involved in politics or foment unrest against the government, but stressed that it would continue to be critical of policies it deemed not in the people's best interest.

President Susilo Bambang Yudhoyono, who also addressed the gathering, backed Said Aqil's statements and highlighted the need for NU to support the stability of his administration. "We need to stand united, and not create an unstable political environment," Yudhoyono said.

Religious Affairs Minister Suryadharma Ali, meanwhile, praised NU for its sustained and important role in shaping a largely tolerant Muslim society over the decades. "NU's services to the people have been outstanding, both during the struggle for independence and now," he said.

The importance of the organization in developing the country could not be stressed enough, he added, calling on NU to step up its efforts to that end.

Thousands of NU supporters from across the country were bused in for the anniversary celebrations, causing massive traffic jams in Senayan and surrounding areas.

Before the start of the celebrations at 9 a.m., traffic to Senayan was backed up for several kilometers, stretching all the way up Jalan Sudirman to the Hotel Indonesia traffic circle in Central Jakarta.

The chaos was not limited to the streets, though, with scenes of jostling and pushing as thousands of men, women and children tried to crowd into the stadium. There were several reports of people fainting amid the crush.