UN secretary general Ban Ki-moon called on Thursday for Burkina Faso's military to "exercise restraint", after three people died and scores more were injured in protests following a coup.
Ban condemned "in the strongest terms" the coup led by a close ally of toppled ex-leader Blaise Compaore and warned that those responsible for any bloodshed would face justice.
The UN chief called on the country's "defense and security forces to exercise restraint and ensure respect for the human rights and security of all Burkinabe citizens."
"Those responsible for the coup d'etat and its consequences must be held accountable."
It was the second strongly worded statement from the UN chief in two days and came after the Security Council condemned the actions in the west African nation and also demanded the release of the arrested leaders.
It comes after presidential guard members loyal to Compaore burst into a cabinet meeting on Wednesday and seized acting president Michel Kafando, prime minister Isaac Zida and two ministers.
Ban said he was "outraged" by the attack and demanded that the leaders be immediately released.
General Gilbert Diendere, Compaore's former chief of staff, was appointed head of a governing council, which announced a nighttime curfew and shut down the borders.
Diendere ousted a transitional authority that had been charged with running the Sahel nation until presidential and legislative elections are held, the first round of which is due to take place on October 11.