Burkina Faso's senior military officer Isaac Zida, who was in command of the presidential guard, Saturday announced he has seized power as head of state during the interim period.
"I now assume... the responsibilities of head of the transition and of head of state to assure the continuation of the state" and a "smooth democratic transition", Xinhua cited Col. Zida as saying in a statement aired by a local television station.
Zida said an interim body would be established in order to restore constitutional order.
He also ordered the closure of borders and announced the invalidation of a statement made Friday by the country's army chief Nabere Honore Traore stating he has assumed power as head of state on a transitional basis.
Traore's declaration was rejected by demonstrators and sparked waves of protests Friday.
On Thursday, hundreds of thousands of people turned out in the streets of the capital to prevent members of parliament from voting to amend the constitution, a move that would have allowed 63-year-old President Blaise Compaore to compete for another term of presidency.
Compaore came to power after overthrowing his brother Thomas Sankara in a coup in 1987.