Buses loaded with Pemuda Panca Marga (PPM) supporters chanting nationalist slogans and clad in military uniforms and berets have cruised the streets of Banda Aceh, while members of the Indonesian Mujahidin Council, whose leader is charged with terrorist offences, unloaded aid from Australian transport planes at the city's main airport.
The sons of military veterans, the members of PPM are best known for intimidating human rights activists and other critics of military policy in Aceh, which has been the scene of a brutal 29-year-long separatist insurgency.
In May 2003, hundreds of PPM members stormed the offices of the Committee for Missing Persons and Victims of Violence (Kontras) in Jakarta, destroying office equipment and beating members of staff. The chief of police later said his officers were all in meetings and unable to answer calls for assistance.
Days earlier, the organisation issued a strongly worded statement critical of the government's decision to pull out of peace talks with the Free Aceh Movement (GAM) and launch a full military operation against the rebels.
The military claims to have killed at least 2200 GAM members since that time, but has managed to recover only 800 weapons. Hundreds of alleged GAM sympathisers are currently in prisons throughout the country and others have graduated from army-run "re-education" camps.
Kontras' founder, known only as Munir, died of arsenic poisoning during a commercial airline flight to Amsterdam on 7 September. No one has been arrested in connection with his murder and friends and family of the country's best-known human rights campaigner have criticised the government investigation.
Munir died of arsenic poisoning
PPM is the latest in a series of groups with violent records, strong nationalists ideals and links to the military to arrive in Aceh since Indonesia's northernmost province was hit by a devastating earthquake and tsunami on 26 December.
Hundreds of members of the Islamic Defender's Front (FPI), a Jakarta-based organisation with strong ties to arch-nationalist cadres within the Indonesian Armed Forces, have arrived in Banda Aceh in the past nine days.
The group's deputy leader said they planned to open an office in the city's principal mosque but the local imam refused their request.
Hilmy Bakar Almascaty says he expects 5000 laskar forces will arrive in the city over the next few weeks, many of them travelling in Indonesian military C-130 transport planes bringing aid into the region.
"We have a very close relationship with the military. We meet regularly with them to plan our strategy," he said.
While claiming strong Islamic credentials, FPI is widely viewed as a gang of thugs who operate under the control of elements of the Indonesian military.
They are best known for their "anti-vice" campaigns during the fasting month when truckloads of white-clad FPI members smash bars and restaurants, which are allowed by provincial ordinances to operate during Ramadan. The police never intervene to protect the property lost in these attacks.
MMI activists could be seen working at the Banda Aceh airport, assisting with the delivery of aid from Australian military aircraft just hours before the scheduled visit of US Secretary of State Colin Powell.
The MMI is chaired by accused Jemaah Islamiya (JI) amir Abu Bakr Bashir, who is currently standing trial in Jakarta on charges that he sanctioned the truck-bombings of the JW Marriott Hotel in Jakarta in August 2003.
Jemaah Islamiya is listed by the United Nations and the US Department of State as a terrorist organisation. Its goal is the creation of a vast, Southeast Asian Caliphate.
Abu Bakr Bashir sits in a
courtroom during his trial
Dozens of JI operatives are serving lengthy jail sentences for the 2002 bombing of a Bali nightclub that claimed more than 200 lives. Analysts say the organisation is committed to the creation of an Islamic Caliphate extending from southern Thailand and the Philippines to the shores of Australia.
Local religious leaders worry the presence of the groups, some of which espouse an uncompromising Wahhabi brand of Islam that is not widely practiced in Muslim Southeast Asian nations, could destabilise the situation.
"Before the tsunami there was very little support for these organisations in Aceh, only a small number of young men and we try to reach out to them and bring them back to our traditional ways," says Muslim Ibrahim, chairman of the Acehnese Ulama Council.
"If any of them attempt to give speeches that are too strict, then we will intervene to prevent it. We have anticipated some of these kinds of problems."
Aceh is the only province in Indonesia to implement a limited version of Islamic law. Adopted in 2002, it requires Muslim women here to wear headscarves, bans private entertainment venues and the sale of alcohol. Banda Aceh's cinema was closed in 1998, and bars outside the major hotels have been banned for many years.
Indonesia's People's Welfare Minister Alwi Shihab, who in an interview last year trumpeted his organisation's campaign against the creeping influences of a radical Islamist doctrine in Indonesia, sees nothing sinister in the various groups coming to Aceh.
"I am not concerned at all," he says. "These are people who have travelled a great distance in order to help their fellow citizens in Aceh."