Analysts say the main reason is that the group serves as a way for people to express dissent in countries whose governments don't tolerate opposition. Also, the group's tactics -- or means of propaganda -- seem to play a significant role in its popularity.
Persecuted And Prosecuted
Hizb ut-Tahrir (HT) is a highly secretive organization with a well-organized structure and strict hierarchy.
In Central Asia, where hundreds of the group's members have been harshly prosecuted in recent years, HT members are generally cautious to speak to outsiders. But in some areas of Kyrgyzstan where HT's popularity is fairly high group, members are becoming bolder in expressing their opinions publicly.
The creation of an Islamic state -- or caliphate -- is the group's proclaimed goal. It officially denounces violence and says the goal should be achieved through peaceful means.
Hizb ut-Tahrir was first created by Palestinians in the early 1950s and the philosophy of the group does not seem to have significantly evolved even as its influence has spread into regions like Central Asia.
Though the HT in Central Asia seeks the overthrow of the region's secular regimes in order to establish a caliphate, HT members are usually unable to articulate any program for governing the people who are outside of the imposition of Shari'a.
No Real Plan To Govern?
For example, HT members cannot explain what their agricultural or health-care policies would be if the group came to power. The group generally shows intolerance toward other religions and indeed other sects of Islam, which would be a great problem for them in Central Asia today as there is a significant Christian population and some Shi'ites (notably in eastern Tajikistan).
Official statistics in Kyrgyzstan (the government's Institute for Strategic Studies, published at ferghana.ru) put HT membership as high as 10,000 in that country alone.
The group's activists claim they have tens of thousands of members and many sympathizers in Central Asia.
Studies have shown that HT works as a network organized into cells. Each cell is called a "halqa" and comprises between four and seven people. Only the halqa supervisor knows the next level of leadership, but he does not know the whole hierarchy. Such a structured organization prevents the domino effect of prosecution or imprisonment in case of a member being detained and interrogated.
Observers also say HT members take an oath when they join the party. It is not clear whether there is a formal procedure for leaving the party. Former members, if there are any, have apparently not sought publicity.
Lectures And Seminars Spread Ideas
Maksat Sabirov ( name has been changed to protect his identity), 33, is a Hizb ut-Tahrir member. Speaking to RFE/RL from the southern Kyrgyz town of Karasuu, he admits he also took oath when he joined the group 10 years ago.
Sabirov says he would comment on political issues or explain HT's goals and political positions (including HT's view of the upcoming Bishkek summit of the Shanghai Cooperation Organization). But he is reluctant to talk about the group's means of propaganda.
However, Sabirov admits that lectures and seminars -- or "lessons" as he calls them -- are the group's most used means of attracting new members.
"Hizb disseminates ideas. It organizes lessons for interested people and teaches them in cells, halqa," he said. "Those satisfied with the ideas join it. That's all."
Sabirov adds that group gatherings are held in accordance with Shari'a, or Islamic law, which requires that men and women be segregated.
HT also disseminates its ideas through leaflets, books, and magazines. Advanced technology, often with computers and with printers, has made printing easier and cheaper than it previously was.
Critical Of The West
HT distributes a newspaper called "Ong -- Al-Waie" (Awareness) in the Uzbek language. Each member has to buy every issue. For potential members and interested parties, the newspaper is distributed for free, Sabirov says.
HT sends "Ong -- Al-Waie" to media organizations and embassies. The newspaper's coverage is not limited to issues of faith and Islam. It also addresses a wide range of political issues and is usually highly critical of the West, especially the United States. It also puts harsh criticism on local governments and their leaders, and calls Uzbek President Islam Karimov a Jew (HT also calls Pakistani President Pervez Musharraf a Jew).
That these methods are effective is clear since HT members give standard answers to basic questions -- seemingly memorized from the same texts -- and share a pessimistic view of the future under secular governments. Central Asian government officials have called such uniform indoctrination to be brainwashing.
In recent years, the group has resorted to the Internet as its penetration slowly and steadily grows in Central Asia.
Different Means Of Promotion
In rural areas, where there is virtually no access to the Internet, HT uses different tactics.
"Hizb ut-Tahrir has existed [since 1953]," Sabirov said. "It uses the Internet wherever there is access to it. If there is no Internet, we distribute leaflets, for example. You know, there are gatherings in villages, when people get together and eat rice pilaf, for example. We distribute ideas there. The means of distribution are not important. Ideas are important. For different places, we have different ways to disseminate them."
Lately, audio and video equipment have been added to HT's arsenal. Shavkat Kochkorov of the Kyrgyz National Security Service addressed journalists in the southern Kyrgyz city of Jalal-Abad earlier this month.
"They have means of transportation [and] the best video and audio equipment," Kochkorov said. "They come to places where Muslims -- elders and imams -- gather and propagate their ideology among the people. They openly say: 'There's little time left until we will have a caliphate, and then in the caliphate you all live very well, your life will improve and you will have freedoms.'"
Sabirov says that HT distributes audio and DVDs in the cities as well as in villages.
Nowadays, a simple DVD player is affordable for many Kyrgyz or Uzbek families at the price of $30-$50.
Gaining Prominent Supporters
Sabirov says that HT collects membership fees like any other political party. Each party member is expected to pay 10 percent of their income to the party.
Toigonbek Kalmatov, who heads the Kyrgyz governmental agency on religious affairs, said last week that many prominent people are HT members.
"They have attracted many members of parliament, well-known businessmen and government officials and thus [they have] gained financial, moral, and other support for their activity," he said.
Analysts say ethnic Uzbeks from the Ferghana Valley make up the group's core membership.
However, one-fifth of HT's members are representatives of nonindigenous ethnic groups such as Russians, Tatars, Chechens, Meskhetian Turks, Kurds, and others.
In recent years, mostly women, youths, and former convicts have been behind HT's membership growth, with those aged 18-35 being the generation mainly joining HT.
Most Central Asian officials insist that HT is a militant group and must be eliminated. Kalmatov said that weapons were found in recent raids of HT places in southern Kyrgyzstan.
Violent Or Peaceful
"They have changed their tactics," Kalmatov said. "They aim to change the constitutional system with force; not through peaceful means, but by taking up arms. Weapons and ammunition, bullets and grenade launchers were found [in HT members' houses]. They are using all kinds of methods in order to achieve political power."
HT has denied accusations that it seeks a violent overthrown of the current political systems in Central Asia.
Sabirov says his party is able to achieve its goal through peaceful means and added that there is no need to take up arms.
For him, the secret of HT's success is obvious: "We speak with people in their language," Sabirov says.
"A representative of Uzbekistan's Fidokorlar once said: 'Hizb ut-Tahrir's members [go to the cotton field] on a bike and pick cotton with farmers, sit at computer desks with an IT specialist, play computer games together, and meanwhile disseminate their ideas. But our Fidokorlar members go to meetings with cotton-growers in Mercedes Benzs wearing white suits. [HT members] are inside the society and [Fidokorlar members] are outside [of society],'" he said. "Yes, I recall him saying so once. And it is absolutely true."
(RFE/RL Uzbek Service correspondent Elmurod Jusupaliev contributed to this report from Bishkek.)