Omurbek Tekebayev was arrested after arriving at the Central Asian country's main airport outside the capital Bishkek on a flight from Vienna.
About 300 people gathered in front of the State Committee for National Security, or GKNB, in Bishkek, later in the day to call for Tekebayev's release.
"The detention of the famous politician Tekebayev at night in the airport looks like the detention of a terrorist," former Kyrgyz President Roza Otunbayeva told journalists.
Tekebayev, the leader of Kyrgyzstan's Ata-Meken party, has vigorously denied the charges and returned from abroad despite knowing he could face detention. Members of Ata-Meken at the protest said his arrest was illegal due to procedural violations.
Also Read
Kyrgyzstan has opened a string of criminal cases against opposition figures in recent months that critics allege are politically motivated.
The largely Muslim nation, a former Soviet republic, is set to hold presidential election elections in November.
Disclaimer: No Business Standard Journalist was involved in creation of this content