The German football club said they held a "detailed and clarifying conversation" with Mazraoui about his "Instagram posts in connection with the terror against Israel almost two weeks ago which led to irritation and criticism."
Jan-Christian Dreesen, Bayern Munich's chief executive said the Moroccan player "credibly assured us he rejects terror and war" and "regrets if his posts caused irritation."
In the statement issued by the German team, Mazraoui was quoted saying: "I condemn every kind of terrorism and every terrorist organization."
Bayern coach Thomas Tuchel on Friday said, "I'm very happy with the club's statement, I back it 100 percent — also personally."
The probe by Bayern Munich came after Mazraoui took to Instagram in the wake of the deadly attack on Israel by Hamas gunmen. He had put up several pro-Palestinian posts, including one that called for "victory" for "our oppressed brothers in Palestine."
The messages, which have since been deleted, were posted after Hamas militants stormed into Israel from the Gaza Strip on October 7, and killed at least 1,400 people, mostly civilians who were shot, mutilated or burnt to death on the first day of the raid, according to Israeli officials.
Israel said around 1,500 Hamas fighters were killed in clashes before its army regained control of the area impacted by the attack.
The Hamas health ministry in Gaza reports over 3,700 Palestinians, mainly civilians, have been killed across the Gaza Strip in relentless Israeli bombardments in retaliation for the attacks by the Islamist militant group.