OUAGADOUGOU (Reuters) - Burkina Faso's interim President Isaac Zida said on Monday that the army would quickly cede power to a transitional government headed by a consensual leader, in a bid to calm accusations that it had seized power in a military coup.

The country's longtime president Blaise Compaore stepped down on Friday after two days of mass protests over his bid to extend his rule through a constitutional amendment.

On Saturday, the military appointed Lieutenant Colonel Zida as interim head of state in a move criticised by opposition politicians, the African Union and Western powers seeking a return to civilian rule.

"Our understanding is that the executive powers will be led by a transitional body but within a constitutional framework that we will watch over carefully," Zida told a gathering of diplomats and journalists in the capital Ouagadougou, without giving a timeframe for the changeover. "We are not here to usurp power and to sit in place and run the country but to help the country come out of this situation,"he added.

The announcement followed crisis meetings late on Sunday between Zida and opposition leaders after thousands gathered to denounce his appointment in the central Place de la Nation - the scene of violent protests last week in which the parliament was set alight.

Under the West African country's constitution, the head of the National Assembly should take office if the president resigns, with a mandate to organise elections within 90 days. However, the head of the National Assembly has reportedly to have fled the country, along with other senior members of Compaore's regime.

Compaore himself arrived in neighbouring Ivory Coast on Saturday, the government there said in a statement.

Later on Sunday, the army opened fire after crowds flocked to the state TV headquarters in anticipation of the announcement of a new leader. One protestor was killed.

Calm had returned on Monday with banks reopening and traffic began filling up the dusty streets of the capital. An overnight curfew remained in place.

Zida's appointment marks the seventh time that a military officer had taken over as head of state in Burkina Faso since it won independence from France in 1960. It was previously known as Upper Volta.

Benewende Stanislas Sankara, a member of the opposition party UNIR/MS, expressed concern at the army's role in overseeing governance. "Nobody can place their confidence in the army. But the military authorities in power now appear to be acting in good faith," he told Reuters.