Timothy Mapes, Jakarta – Indonesia's move to expel a US citizen, who has become the most highly regarded expert on terrorism in Southeast Asia, could renew questions about the determination of the world's largest Islamic country to fight violence by extremist groups.

The expulsion of Sidney Jones, director for Southeast Asia of the International Crisis Group, also appeared to be a major escalation of increasingly authoritarian controls over freedom of speech in the run-up to next month's presidential election. The US Embassy said it is "very concerned" about Ms. Jones's expulsion, which it said stood "in stark contrast to the impressive progress made by Indonesia in recent years in developing a democratic civil society."

Based in Brussels, the International Crisis Group is an independent, nonprofit organization that works to prevent and resolve conflicts. It is chiefly funded by foreign governments.

At a news conference, Ms. Jones said immigration officials told her the decision to force her to leave the country was driven by a complaint from Indonesia's intelligence service about her work. She added, however, that she has been unable to learn the specific nature of the complaint, despite months of trying without success to contact the agency.

"We must have touched a couple raw nerves. I just don't know what those raw nerves are," Ms. Jones said. She said she planned to leave the country by the weekend, along with an Australian colleague who was expelled.

The government ordered the two to leave the country "immediately" in a letter delivered to the organization late Tuesday. Ms. Jones, 52 years old, began her work at the group's Jakarta office in May 2002 and quickly gained attention for a series of detailed reports about the background and extent of Islamic terrorist groups in Indonesia, as well as their connections with international networks such as al Qaeda. Ms. Jones issued reports on separatist conflicts in Indonesian provinces such as Aceh and Papua that were frequently highly critical of Indonesian government policies.

Ms. Jones's reports on terrorism were particularly notable because their detailed and meticulous use of court records and interviews helped to dispel the widespread perception in Indonesia at the time that terrorism wasn't a serious problem. Before joining International Crisis Group, Ms. Jones was the Asia director for New York-based Human Rights Watch, a job that helped her develop extensive contacts among Indonesia's fundamentalist Islamic community, which was persecuted during the authoritarian regime of former Indonesian President Suharto.

During August 2002, for example, Ms. Jones issued a report that explored extensive and longstanding links between al Qaeda and an Islamic boarding school in the Indonesian city of Solo. Two months later, several alumni from the school helped to bomb nightclubs on the island of Bali, killing 202 mostly Western tourists.

The Indonesian government is holding the school's co-founder, Abu Bakar Baasyir, under its antiterrorism laws, which allow for detention without charge.

Many Western governments believe Mr. Baasyir leads a Southeast Asian terrorist group called Jemaah Islamiyah, but Mr. Baasyir denies that charge, and an effort to prosecute him was rejected by an Indonesian judge last year.

At a news conference Monday, Indonesian President Megawati Sukarnoputri denied that the move to oust Ms. Jones showed her government is softening its antiterrorism drive. "The Indonesian government is seriously fighting against terrorism without any pressure from any party because we know that terrorism is bad for Indonesia as well as for the world," she said.

Ms. Megawati is trailing badly in opinion polls ahead of the July 5 presidential election, and steps to fight back against criticism by foreigners are frequently popular with Indonesian voters. But the leading contender, former security minister Susilo Bambang Yudhoyono, yesterday called on the government to explain the decision more thoroughly. "Let us hope the expulsion doesn't damage the democracy that we are building," he said.

Hendropriyono, the director of the State Intelligence Agency, couldn't be reached for comment yesterday. But during recent days he has publicly complained about Ms. Jones's reports.

In an interview published Monday in Tempo, an Indonesian newsmagazine, Mr. Hendropriyono was quoted as saying Ms. Jones's reports were "not all true." He added: "There must be steps taken against people who aren't liked by the people of Indonesia."