DAKAR, April 1 (Xinhua) -- Guinea-Bissau's Prime Minister Carlos Gomes Junior was briefly detained on Thursday by military officers amid renewed fears of coup in the Atlantic Ocean country in West Africa.

Instability including the 1998-1999 civil war has haunted the country of 1.5 million population since its independence from Portugal 35 years ago. Coup attempts have repeatedly hit the headlines in Guinea-Bissau, especially since 2008.

In the latest incident, which is already seen by many as another coup d'etat, Minister of Territorial Administration Luis Sanca was also taken hostage after the military officers broke into the office of the prime minister in the capital Bissau.

Before nabbing Gomes, the officers went to the United Nations offices in Bissau to pick up the former head of marines, the rear admiral Jose Americo Bubo Na Tchute, who had been accused of plotting a coup d'etat in August 2008.

The ex-chief of Guinea-Bissau's marines took refuge there after returning to Guinea-Bissau in a canoe from Gambia on Dec. 28, 2009.

The UN office in Guinea-Bissau known as UNOGBIS had previously indicated willingness to settle the issue in a "peaceful and legal" way.

On Thursday morning, national radio stopped broadcasting programs and started playing military songs.

In the capital city, banks and office buildings were shut down. On the streets, only military vehicles could be seen moving, witnesses told Xinhua by phone.

In defiance of the military movement, hundreds of people gathered in front of the office of the prime minister protesting against "coup d'etat."

A senior army officer Antonio Indjai threatened to kill the prime minister if the protesters refused to stop attracting crowds in the streets.

Gomes was nominated in January 2009 by President Joao Bernardo Vieira, who was assassinated on March 2, 2009 by rebellious soldiers at his residence.

The West African country of 1.5 million population foiled a mutiny after holding a legislative election in November 2008, when the African Party for the Independence of Guinea-Bissau and Cape Verde (PAIGC) won the victory.

The Interior Ministry reported another "coup attempt" in early June 2009, just days ahead of the June 28 presidential election which was won by PAIGC's candidate Sanha.

The country is among the poorest in the world, being ranked the 175th out of 177 nations in the U.N. Development Program's Human Development Index.

With a jagged Atlantic coastline, Guinea-Bissau is chosen by traffickers as a major hub for the flow of cocaine from Latin America to Europe