Officials in Guinea-Bissau say the head of the country's new interim government has named a prime minister to help lead a transition following last month's military coup.

The officials said Wednesday that Manuel Serifo Nhamadjo selected former finance minister Rui Duarte Barros to be prime minister.

The tiny African nation has been at an impasse since April 12, when soldiers seized power and arrested interim President Raimundo Pereira and his prime minister. Both men later fled the country.

The coup derailed a presidential run-off election to replace late President Malam Bacai Sanha, who died in January.

It also stalled talks with the Economic Community of West African States, or ECOWAS. The regional bloc has imposed diplomatic and economic sanctions on the junta and warned it would deploy a peacekeeping force to Guinea-Bissau if constitutional rule is not restored.

About 650 troops from Nigeria, Burkina Faso, Senegal and Togo are expected to arrive in the capital, Bissau, beginning Friday and will be stationed at army barracks outside of the capital.

A new interim government headed by parliamentary speaker Nhamadjo is expected to be installed next week, with ECOWAS's backing. The regional bloc's President Kadre Desire Ouedraogo said ECOWAS is supporting what is expected to be a year-long transition period for Guinea-Bissau.

Guinea-Bissau has endured numerous coups and attempted coups in the past 30 years. It is also a key transit point for international drug traffickers.