The head of the opposition Democratic Movement Kyrgyzstan, Japar Jeksheev, suspects the government had something to do with the disappearance of the long-time critic Akun.
"The kidnapping of Akun is typical for the government. The National Security Service is using the methods of 10 years ago," Jeksheev said.
But Chinara Asanova, the spokeswoman for the National Security Service (SNB), said the organization denies any part in the rights activist's disappearance.
"The SNB officially declares that it has no connection to the disappearance of human rights defender Tursunbek Akun," Asanova said.
Akun left his home in Bishkek a week ago, telling his wife someone from the country's SNB wanted to speak with him downtown. He was accompanied by a relative, who later confirmed the two men went downtown. The relative said that at one moment he looked away for a few seconds and, when he looked back, Akun was gone.
The spokesman for Kyrgyzstan's Interior Ministry, Joldoshbek Busurmankulov, denied Akun is currently being held by any government agency and said there is no reason to detain him.
"No state body, no law enforcement agency is interested in holding Akun. Currently neither the Interior Ministry nor the SNB is holding him," Busurmankulov said.
Denials from government officials are unlikely to convince those who support Akun. The rights campaigner has been detained many times for his part in organizing demonstrations. Several officials have previously accused him of inflaming the passions of crowds, and he has been branded by the government as a troublemaker. One official went has said that wherever Tursunbek Akun went there was bloodshed.
Prior to his disappearance, Akun was collecting signatures as a part of a campaign to force the country's president to resign. Nurlan Motuev of the People's Patriotic Movement of Kyrgyzstan, which Akun heads, said the signature-collecting campaign prompted authorities to kidnap Akun.
"We have an idea that special services kidnapped him [Akun] because our movement started to gather signatures to get [President] Askar Akaev out of office before his term was over," Motuev said. "Every day we gathered 1,000 to 2,000 more signatures. It was going well. They [the authorities] became afraid and kidnapped him."
Akun's disappearance three months before parliamentary elections in Kyrgyzstan is certain to raise tensions as the country approaches elections in late February. His disappearance could become a prominent issue in opposition campaigning.
Kyrgyzstan has seen many mass protests and demonstrations, especially in the days prior to and just after the last parliamentary and presidential elections.
(Amirbek Usmanov of the Kyrgyz Service contributed to this report.)