(Reuters) - Some things in the central Jakarta district of Matraman have barely changed since the late 1960s, when United States President Barack Obama lived and played there.

Old men train their racing pigeons on the badminton court and screaming children chase each other through the winding, grimy alleyways. But if Obama does decide to drop by his old neighborhood when he visits Indonesia next week, he may notice change around the community's mosque.

The local mosque has become a meeting spot for members of the small but vocal Islamic Defenders Front (FPI), an extremist group famous for smashing up bars that serve alcohol and which made headlines when its followers assaulted several elderly men and women at a peaceful interfaith rally in 2008.

"Now there are so many radicals around here. We don't agree with them but there's definitely more than there was before," said Ali Rully, a pensioner who was a high school student when little "Barry" Obama lived here.

Indonesia is the world's most populous Muslim-majority nation but is officially secular and has long been seen as a bastion of moderate Islam.

But the emergence of pockets of radicalism and a shift from Indonesia's traditional form of Islam, infused with Hinduism and other influences, toward a stricter form of the religion are cause for concern for some moderate Indonesians.

Police recently unearthed a new al Qaeda-linked cell in Sumatra's Aceh province and this month killed one of the world's most wanted militants, Dulmatin, who was involved in the 2002 Bali bombings that killed 202 people, foreigners and Indonesians.

The recent cases serve as a reminder to the vast majority of moderate Muslim Indonesians that extremism is alive in Indonesia.

One Matraman resident, who asked not to be named, said she had detected an increasingly anti-Western tone in some of the sermons broadcast by the local mosque.

Obama is a Christian but was listed in his primary school records as a Muslim, probably because his father and step-father were Muslims. As a child in Jakarta, he would have been exposed to a very moderate form of Islam by his Javanese stepfather, Lolo Soetoro, say locals.

Obama's former neighbors, however, said the recent revelations of new jihadist cells show that times have changed in Indonesia.

"There was nothing like that in those days, when Obama was a kid here. None of these, what do you call them, terrorists," said Agus Salam, who sells gado-gado, a local vegetable dish, from a Matraman stall and who remembers the president as a chubby-faced little boy.

"Religion then and now is different. Then, religion was not a big issue. Now religion has changed, everyone seems to have all these different beliefs. There's this type of Islam, that type of Islam, another type."

Radical groups were kept tightly in check under the autocratic former president Suharto who ruled for three decades until he was ousted in 1998. His fall from power paved the way for greater democracy -- including the freedom for groups like the FPI to express their views openly.

"Maybe our government at the moment is not firm enough. Back in Suharto's day, the government was much tougher," said Rudy Yara, 61, who remembers teasing Obama about his tightly curled hair as a child.

Not everyone has such a rosy view of the past. One Matraman resident, who asked not to be named, remembered feeling scared at night in the 1960s in the West Java city of Bandung because of the fear of attacks by extremist group Darul Islam (DI).

Many of today's extremist groups such as Jemaah Islamiah have their roots in DI, which was repressed by the Indonesian army in the 1960s.

Noor Huda Ismail, an Indonesian expert on radical Islamist groups, said he thought that radicalism was growing in Indonesia, partly because of the effective use of internet technology by extremist groups.

"Yes, it's probably more widespread now but I would prefer to live now than in Obama's time, at least we now have freedom of expression," he said.

Editing by Sara Webb.