ALMATY, Kazakhstan (AP) — A senior U.S. diplomat said Wednesday that he hopes the upcoming trial of a prominent opposition leader in Kazakhstan is conducted fairly and does not set back democratic reforms in the Central Asian nation.

Assistant Secretary of State Robert Blake said the U.S. will closely follow the fate of Vladimir Kozlov, who has been charged with seeking the overthrow of the government and other crimes.

Specifics of the overthrow charge have not been made public. Kozlov is also charged with fomenting last December's unrest in the town of Zhanaozen, where 14 people were killed by police firing on striking oil workers.

Kozlov's Alga party says the trial, which opens Thursday, is aimed at eliminating opposition to the strongman President Nursultan Nazarbayev's regime.

Kazakhstan, a vast former Soviet nation with copious oil and gas reserves, is seen as a reliable partner by the West and cooperates closely on security and energy, but has come under withering criticism from rights groups for its weak democratic credentials.

Blake said Kazakhstan's authorities need to work on ensuring they address popular grievances to avoid violent unrest.

More than 30 people were killed in a string of attacks last year that authorities linked to radical Islamic organizations.

"Many Kazakhstanis we have spoken to have said they understand that a lot of the attacks we have seen ... are because of problems that are Kazakhstan-based, it's not an international terrorist network," Blake said.

One area of particular concern to the United States was the approval in October of a restrictive law on religion that requires faith groups in the mainly Muslim nation to renew their registration. The procedure is all but guaranteed to exclude smaller groups, including minority Christian communities. It also forbids prayer in the workplace.

Supporters of the law have argued that it will help combat religious extremism.

Blake said that poor implementation of such rules could have the opposite effect.

"Those kinds of things if not properly handled can lead to greater grievances against the government and again can indirectly fuel the kinds of terrorist incidents that we've seen," he said.