The three-week general strike ended after a military crackdown and the appointment of a consensus prime minister.
Fear
The home of the army chief was attacked, and shops looted as junior officers went on the rampage, according to the AFP news agency.
The soldiers allege that President Lansana Conte has gone back on his pledge to increase their wages after an army mutiny in 1996.
They had been promised back-pay.
"We have received about 20 injured between Wednesday and Thursday... many of the injuries were gunshots in the arm, back or in the face from stray bullets," Amidou Cisse, a doctor at the Kindia hospital, told the AP news agency.
More than 120 people died during the protests in January and February.
The BBC's West Africa correspondent Will Ross says that although the military remained loyal to President Conte, partly as a result of a series of pay hikes, some have wondered how long the army would continue to back him.
This is the first sign of serious unrest since an interim prime minister was appointed to take over the running of government affairs.
The fear is that unless order is restored immediately, this could all too easily develop into a full-scale mutiny within the national army, our correspondent says.