BRAZZAVILLE (Reuters) - Congo Republic on Friday released Marcel Pika, a naturalized U.S. citizen detained for nearly two years, according to the U.S. embassy in the capital, Brazzaville.

“We are happy about the liberation of Mr. Pika. We thank the Congolese government for this action. We hope Mr. Pika will be able to join his family in the United States,” embassy spokeswoman Jacqueline Mourot told Reuters.

Pika, a retired colonel in Congo’s armed forces, immigrated to the United States in 1999 and became a citizen in 2005. He returned to live in Congo in 2007 and was arrested in March of last year.

His family suspected his detention was caused by his support for opponents of President Denis Sassou Nguesso, who has ruled the country for 33 of the last 38 years, during the March 2016 presidential election.

Congo’s government did not speak publicly about the case and a government spokesman declined to comment on Friday.