Captain Ibrahim Traore was appointed as president of Burkina Faso on Wednesday, according to an official statement, after the West African country's second coup in less than nine months.
Lieutenant-Colonel Paul-Henri Sandaogo Damiba seized power in January, only to be toppled last weekend by newly emerged rival Traoré, at the head of a faction of disgruntled junior officers.
Military and popular dissatisfaction with the campaign to resist an islamist insurgency is cited as the main contributor to instability in the impoverished Sahel nation.
Burkina has been struggling for the past seven years against a jihadist campaign that has claimed thousands of lives, forced nearly two million people to flee their homes, and left more than a third of the country outside government control.
Wednesday's military communiqué said that Traoré would now be the "guarantor of national independence, territorial integrity ... and continuity of the State."
Damiba fled to Togo following a two-day standoff over last weekend.
What is Russia doing in Burkina Faso?
Delegates from the Economic Community of West African States (Ecowas) wrapped up a fact-finding mission to Burkina on Tuesday and held meetings with religious and traditional leaders and Traoré.
Speculation has risen that Burkina's new leader may follow other fragile regimes in French-speaking Africa and forge close ties with Moscow at the expense of France, the region's former colonial power and traditional ally.
Last weekend's takeover was marked by violent anti-French protests and the sudden emergence of Russian flags among demonstrators.
On the streets, demonstrators' slogans included "France get out", "No to Ecowas interference", and "Long live Russia-Burkina cooperation".
The United States has warned the junta of the risks of allying with Russia, saying they condemned "any attempt to exacerbate the current situation in Burkina Faso.
"We strongly encourage the new transitional government to adhere to the agreed-upon timeline for a return to a democratically elected, civilian-led government," a State Department spokesman said earlier this week.
Ibrahim Traoré has promised to stand by a pledge given by Damiba to restore civilian rule by July 2024.
