Brazzaville - A naturalized US citizen who was detained in the Republic of Congo for more than a year has been released, the United States Embassy there said on Friday.Marcel Pika is a retired colonel who served in the Republic of Congo's military. He was arrested early last year and held for "inciting disorderly conduct" amid unrest and other detentions that followed President Denis Sassou N'Guesso's re-election.US Embassy spokesperson Jacqueline Mourot said Pika, 70, was freed on Friday without further judgment."The US Embassy is very grateful to the government of Congo for having decided today to release Mr. Pika. We think this is a good step forward in the framework of good relations between our two countries," she said.The US State Department requested Pika's release in June, citing concerns over his diabetes and the conditions under which he was being held.Pika and his family left the Republic of Congo and eventually settled in the US state of Nebraska as refugees in the late 1990s. Nearly a decade later and after obtaining US citizenship, Pika returned to his home country with his wife. Republic of Congo is often overshadowed by its much larger neighbour, Democratic Republic of Congo.Pika was close to General Jean-Marie Michel Mokoko, who placed third in the 2016 presidential election. Mokoko was also arrested after the vote on charges of undermining state security.Human rights groups have criticized Sassou N'Guesso for violations and called for the release of political prisoners. The country's March 2016 election came five months after a constitutional referendum removed term and age limits that would have barred the president, then 72, from running. He has ruled the Central African country for more than 30 years.