OUAGADOUGOU (AFP) - The military officer who took power after the fall of Burkina Faso president Blaise Compaore was on Wednesday named prime minister in the west African country's interim government.

Lieutenant-Colonel Isaac Zida's appointment by interim president Michel Kafando comes with Burkina Faso under international pressure to see through a civilian transition.

"The president of the transition decides that... Mr Yacouba Isaac Zida is named prime minister," said a decree issued by Mr Kafando and read out by a top government official.

Mr Kafando, a veteran diplomat, was sworn in as Burkina Faso's interim president on Tuesday to oversee a year-long transition to civilian rule after the turbulent ouster of Mr Compaore's regime on Oct 31.

The appointment of 49-year-old Zida was agreed between politicians and army leaders, according to a senior military officer.

"It was on this understanding that we gave the post of president... to civilians," the officer added.

Mr Zida, then second-in-command of the presidential guard, was installed in a military power grab in the immediate aftermath of the uprising against longtime-leader Compaore.

Mr Kafando, a 72-year-old former foreign minister and United Nations ambassador, has pledged he would not let the country become a "banana republic".

Poised to formally take over on Friday from the interim military regime, Mr Kafando emphasised his "humility" as a leader aware that he temporarily held "power that belongs to the people".

The landlocked nation of 17 million people "could never become a banana republic", he added, declaring it was the "first elementary duty of a citizen" to respect the Constitution.

Burkina Faso is one of the world's poorest nations - almost half the population live on less than US$1 (S$1.25) a day and many are subsistence farmers. But the country has positioned itself as a mediator in regional crises. It is also a key ally in Western operations against Al-Qaeda-linked groups in West Africa.

Mass unrest erupted in late October over Mr Compaore's bid to change the Constitution, which would have allowed him to extend his 27-year rule of the former French colony.

Mr Kafando, who served as Burkina Faso's UN envoy from 1998 to 2011 and briefly as foreign minister in 1982 to 1983, was chosen to head the transition after tortuous negotiations between the military, political parties and civil society groups.

He is barred from standing in elections scheduled to be held in November next year under the transition deal.

The African Union had warned that the deeply poor country would face sanctions unless it chose an interim leader, and it welcomed Mr Kafando's appointment.

However, the decision to hand power to a man closely associated with the former regime raised suspicions for many.

"Compaore said for 27 years that he was not thirsty for power, yet he remained firmly in his job," said street seller Amadou Sawadogo, 37.

Mr Kafando heads a 25-member transitional government, and a civilian will also head a 90-seat Parliament, known as the National Transitional Council.

"It is an awesome responsibility that falls to me. I already foresee the pitfalls and the immensity of the task," Mr Kafando said after he was named on Monday.

The United States on Tuesday congratulated the country over the peaceful formation of an interim government.

It urged Mr Kafando "to build on the momentum of the past two weeks and to select individuals to serve in the transitional government who are firmly committed to a democratic, civilian government," said State Department spokesman Jeff Rathke.

During the uprising against Mr Compaore, protesters set the Parliament building ablaze and attacked other official premises in the capital and other cities in violence not seen since a wave of army mutinies in 2011.

Mr Compaore was 36 when he seized power in a 1987 coup in which his former friend and one of Africa's most loved leaders, Mr Thomas Sankara, was ousted and assassinated.

He held on to power in the following decades, being re-elected president four times since 1991.

Mr Compaore has taken refuge in neighbouring Ivory Coast, where he is living in a luxury villa owned by the state.