PORONG PRISON, Indonesia -- A sweeping crackdown on terrorism in the past decade has spawned a new problem in Indonesia, the world's most populous Muslim nation: Militants in jail are recruiting new followers to their cause.

Prisons threaten to undermine the progress made against terrorism here since 2002, when nightclub bombings killed 202 people on the tourist island of Bali, many of them Australians and Americans.

The campaign has assumed global importance because of feared links between Southeast Asian terrorist groups and Al Qaeda. That possibility was underlined by the January arrest of Bali bombing suspect Umar Patek in Abbottabad, the same Pakistani town where Usama bin Laden was killed in May.

The Associated Press was granted two days of unfettered access to Porong prison in early June by the chief warden, who wanted to show that changes were being made to limit the influence of jihadist inmates. While there were improvements, interviews with terrorists and other convicts show how openly the former still court some of the latter.

Porong is a huddle of low concrete buildings set on 40 acres near Surabaya, the country's second-biggest city. It is home to 27 terrorists -- some of the 150 currently held in prisons across the sprawling Indonesian archipelago.

Block F is technically reserved for terrorists but also accommodates about 50 others because of overcrowding. The prison, designed to hold 1,000 inmates, has 1,327.

An elaborate green garden flourishes in the thick heat. Bearded terrorists tend ducks, and fish splash in small ponds. Some militants play sports with other inmates, while others read the Koran or teach Islam to ordinary prisoners.

"We only explain what they should know about jihad," said Syamsuddin, who is serving a life sentence for his role in a gun attack on a karaoke club in Ambon that killed two Christians in 2005. "It's up to them whether to accept it or not."

Syamsuddin was trained in bomb-making by alleged Al Qaeda terrorist Omar al-Farouq during Muslim-Christian conflict in Ambon between 1999 and 2002.

Muhammad Syarif Tarabubun, a former police officer, was sentenced to 15 years for his role in the same attack. He laughed easily and smiled broadly as he explained his extremist views. He said he plans to join a jihad in Afghanistan, Iraq or Lebanon after his likely early release in 2013 for good behavior.

"The death of Usama bin Laden will not ruin our spirit for jihad," he said. "We do it not for a figure. We do it for God's blessing."

Radicalization is common in Pakistan's and Afghanistan's overcrowded prisons, where thousands of terrorists and insurgents mix freely with others, according to a 15-country study by the London-based International Centre for the Study of Radicalization and Political Violence.

In the U.S., Omar Abdel Rahman, the blind sheik behind the 1993 World Trade Center bombing, managed to send inflammatory messages from his prison cell to followers in Egypt. There is debate over whether and how far Islamic radicals are infiltrating U.S. prisons.

One exception may be Saudi Arabia, which is fending off radicalization in prisons through an unusually well-funded and comprehensive program. Its "golden handcuffs" approach of finding wives for captured terrorists and enmeshing them in a web of personal, financial, religious and professional obligations once released is regarded as pioneering.

In Indonesia, experts say, some radicals finish their sentences with an even greater commitment to deadly jihad. Of 120 arrested and 25 killed in raids since February 2010, some 26 had previously been in prison for terrorist acts, according to the International Crisis Group, which researches deadly conflict.

Sidney Jones, one of the group's Southeast Asia terrorism experts, calls Indonesia's prisons the weakest link in the counterterrorism effort. "It's going to undermine everything that the police are doing to break up these networks," she said.

Porong prison, though immaculately clean and far from grim, has ceilings that leak copiously during the rainy season and swarms of mosquitoes at night. Inmates are allowed out of their gray windowless cells from 7 a.m. to 5 p.m. Within Block F, a small shop is a favorite gathering place.

Nearby, nine men wearing traditional Muslim shirts sit on a floor listening intently to a religious lesson by Maulana Yusuf Wibisono, who stockpiled explosives for a 2004 suicide bombing of the Australian embassy in Jakarta that killed 10 people.

These men, part of the ordinary prison population, diligently copy what Wibisono writes on a small white board.

"It's still too early to invite them for jihad," said the 42-year-old terrorist. He is the former leader of the East Java military wing of Jemaah Islamiyah, the group behind the 2002 Bali bombing. "To change their way of life is more important."

Many are in awe of the terrorists' piety and dangerous reputations. Militants also get extra food and other goods, both from supporters and through police attempts at rehabilitation, adding to their sway in prison. Often bearded and clad in robes, sarongs or ankle pants, they stand out from the other inmates.

"Don't judge them as bad guys," said Frans Sandi, who is serving 13 years for murdering his wife. He is a regular at Wisibono's religious instruction. "They are even able to turn bad guys into good."

He is now well versed in the Koran, fasts and never misses the call to pray five times day -- things he had never done in the past.

His budding faith is seen by terrorists as a necessary step toward accepting their extremist version of Islam. While his good behavior and piety may earn him an early release, his debt to the radicals could one day see him used as a terrorist enabler.

"These men understand that wider support for their activities is crucial to the longevity of their movement," says "Jihadists in Jail," a report released in May by the Australian Strategic Policy Institute. "That's why they continue their dakwah (religious outreach) in prison to ensure they can recruit new members and that their own zeal for militant jihad isn't diminished."

Radical preachers, too, have played a role in recruiting behind bars.

In Sukamiskin prison, cleric Aman Abdurrahman won over three students arrested for a hazing death. They were re-arrested last year during a raid on a terror training camp in Aceh province.

Another firebrand cleric, Abu Bakar Bashir, was sentenced recently to 15 years for supporting the Aceh camp. Experts say the imprisonment of Bashir, who co-founded Jemaah Islamiyah, is unlikely to stop him from providing crucial spiritual sanction for terrorism.

Though there have been several more attacks since the Bali bombings, none has been anywhere near as deadly. Analysts credit a crackdown that has netted nearly 700 militants since 2000, including police killings of several key leaders.

But Indonesia, where more than 100 million still live in poverty, lacks the resources to mount a comprehensive program to persuade convicted terrorists to renounce violence. And dozens of Jemaah Islamiyah members are due for release in the coming three years.

"In the absence of a really concerted program, ... you are going to see most of them going back to their networks for the simple reason that those networks are based on family ties," said Carl Ungerer, author of the Jihadists in Jail report.

Nur Achmad, the chief warden at Porong, said he was shocked when he took over late last year to see regular inmates moving freely in and out of Block F. Some had changed their appearance, lengthening their hair and beards in imitation of the militants.

"I have to stop this," Achmad said. "I don't want them spreading radicalism to other inmates."

Prisoners from other blocks are now restricted from entering Block F. Those in the block are allowed to study Islam with the militants but under tighter supervision, including what kind of instruction can be given. Closed-circuit television cameras have been installed.

The extremists have protested Achmad's changes in letters to the police and the justice and human rights ministries. He also received threatening text messages, warning him that his daily routine and family's whereabouts were known, and that a network outside the prison could harm him.

Government officials acknowledge that reforming radicals isn't easy. "This program has so far not yielded optimum results," said Ansyaad Mbai, the head of Indonesia's anti-terrorism agency.

Sometimes the best that can be achieved is a shaky commitment not to wage jihad at home -- potentially exporting the problem abroad.

For Slamet Widodo, sentenced to five years for his role in a 2003 bombing of the JW Marriott hotel in Jakarta that killed 12, violent jihad remains an obligation as long as Muslims suffer injustice.

"But now we know Indonesia is not a proper place for the field of jihad," said Widodo, a veteran of Al Qaeda military training in the early 1990s in Afghanistan.

He is looking further afield while occasionally attending government-run deradicalization sessions.

"If there is a chance to jihad abroad, I would go," he said. "Why not?"