"Two Spaniards holding papers from South Kazakhstan's Episcopate worked as missionaries in [the region], and we detained them. We have also arrested someone from the center for Koran research named 'Dal-Arkam.' I can't say for how long they have been operating but not for long, maybe one or two months," Asylov said.
In the same region, authorities tried to close down the seminary of the local branch of the South Korean-led Synbakyn Protestant church late last year. A foreign missionary had his visa cut short and had to leave Kazakhstan, though he has since been allowed to return.
A local leader of the Ahmadiyya Muslim community, whose doctrine originates from India, has also reportedly encountered visa problems.
These moves followed the compulsory re-attestation of imams in the region, where many mosques operate outside the central Spiritual Administration of Muslims.
The Almaty-based religious expert Murtaza Bulutai suggests that religious communities have found a fertile ground in the republic to promote their doctrines.
"The religious situation becomes more and more complicated. And one wouldn't exaggerate by saying Kazakhstan is becoming a place for religious expansion," Bulutai said.
In an effort to increase control on religious activities in the country, the lower house of parliament, or Majilis, approved earlier this month wide-ranging national security amendments to 11 laws -- including the religion law.
The amendments were then sent on 17 May to the upper house, or Senate, for approval. If approved, they will then go to President Nursultan Nazarbaev for signature before coming into force.
Independent Deputy Amangeldi Aitaly has argued the draft law defends the "historic values" of the Kazakh nation against the expansion of foreign religious doctrines.
Felix Corley is editor of Forum 18, a Norway-based news agency covering religious-freedom issues. He says the amendments will cause unjustified suffering to law-abiding believers.
"The religion law is being amended to punish quite a lot of activities that are not currently subject to punishment. Although the latest amendments were made a little bid milder in the lower house of parliament they still fundamentally restrict ordinary people's right to religious freedom," Corley said.
According to the current law on religious associations, a religious community needs only 10 signatures but has to pay more than $100 to register. Although registration itself is not obligatory, in practice, people can currently be punished for conducting unregistered religious activities.
The proposed amendments to Kazakhstan's law on religion would for the first time formally forbid the activities of unregistered religious organizations.
A new article will be inserted the Code of Administrative Offenses to punish with heavy fines those leading, taking part in, or financially supporting unregistered or banned religious organizations.
"People cannot do anything unless they've been able to persuade the Justice Ministry to register their religious community. This will make it very difficult for small religious communities which are fewer than the number they would need to register. Muslims who want to practice outside the structures of the state-sanctioned Muslim Board would likely face penalties," Corley said.
Kazakhstan would thereby join neighboring Uzbekistan and Turkmenistan in banning the activities of unregistered religious organizations.
The new law would also make missionary activities more difficult. Missionary work without the appropriate registration would attract a fine, while foreigners would be expelled from Kazakhstan.
Corley notes that national security can be grounds for tightening up certain freedoms. However, under international law, national security cannot justify restrictions upon the freedom of religion or belief:
"It seems to many people that this merely the government trying to guarantee its right to remain in power. At the moment authorities in Central Asia are getting very nervous about these revolutions in Georgia, Ukraine, and Kyrgyzstan. Why should believers be restricted just because political leaders are paranoid about their own political survival?" Corley said.
Earlier this year (21 February), President Nazarbaev signed a controversial new law on combating extremist activity. Human rights groups have expressed concerns that the definition of "extremism" in the law is so vague that it could be applied to any religious association.
(Edige Magauin of RFE/RL's Kazakh Service contributed to this report.)