Former Kyrgyz Prime Minister Temir Sariev has been arrested as part of a widening investigation into alleged corruption during the development of the Kumtor gold-mine project.
The State Committee for National Security (UKMK) says Sariev was detained for 48 hours on August 3 on corruption charges ahead of a court decision on pretrial custody.
Sariev served as economy minister in the post-Soviet Central Asian republic in 2011-15 and he was prime minister in 2015-16.
Kumtor has been a target of financial and environmental disagreements for years, and is currently the subject of an ongoing battle for control between the Kyrgyz state and the mine's operator, Canadian Centerra Gold.
On August 2, former Kyrgyz President Askar Akaev arrived in Bishkek for the first time since he was ousted by demonstrations in 2005 to be questioned about the Kumtor case.
The Kyrgyz government has temporarily taken over control of the mine in what President Sadyr Japarov has called a necessary move to address environmental and safety violations.
Centerra has called Kyrgyzstan's actions "wrongful and illegal."
In May, the Canadian firm said it had "initiated binding arbitration to enforce its rights under long-standing investment agreements with the government."
Several former top officials have been arrested in connection with the case in recent months, including former Prime Minister Omurbek Babanov, Deputy Prime Minister Taiyrbek Sarpashev, and former and current lawmakers.
Babanov was released last week and allowed to travel abroad to receive medical treatment for an unspecified illness.