About a dozen people leaving the first-ever Black Lives Matter conference in Cleveland, Ohio, were blasted with pepper spray after protesting the arrest of a 14-year-old boy accused of being drunk.

The crowd taunted Greater Cleveland Regional Transit Authority officers for apparently not calling the child’s mother during the arrest and then blocked a cruiser from leaving with the teenager. Police began pushing the activists back.

“After a gorgeous Movement for Black Lives conference, we started feeling powerful and strong and then we see one of our own being locked up unjustly,” Page May, of Chicago, told the Daily News.

The 14-year-old boy was being escorted to an ambulance by a traffic cop, who was also shown pepper spraying protesters minutes earlier.

The national convening of the Movement for Black Lives started Friday. Cleveland was chosen as the first city for the event in response to the deaths of 12-year-old Tamir Rice and 37-year-old Tanisha Anderson at the hands of police.

Sunday’s incident started at about 4:40 p.m. when authorities took the teenager off a bus with the intent to take him to police headquarters because he “was intoxicated to the point where he was unable to care for himself,” according to Transit Authority officials.

The officers followed standard procedure in taking the boy into custody, officials maintain.

“After police collect pertinent information, juveniles are transported to police headquarters to await release to a parent or legal guardian,” their statement read.

May was about to board a bus back to Chicago after a day of sharing stories of police brutality and racial inequality with the conference, when a crowd gathered to watch over the arrest at a bus stop near Euclid Avenue and East 24 Street.

She dropped her bags to join them.

“To brace ourselves, we started to link arms. That’s when they pepper sprayed.”

A police officer is shown hosing down the protesters with a non-stop stream of the fiery irritant, a video of the encounter shows.

Transit Authority officials described it as a “general burst of pepper spray.”

May was among those hit by the unidentified officer’s second round of spraying as she helped a friend already blinded by the chemical agent.

“The crowd was dispersing at that point, and he just kept going,” May said.

Transit Authority officials also claim protesters attempted to take the teen out of the cruiser.

During the chaos, a protester managed to glean a phone number for the teenager’s mother through an open window as he sat in the back of the police cruiser.

After the boy was examined by paramedics, a woman whom witnesses said was the teen’s mother arrived at about 5:47 p.m. and drove away with her son.

The incident is under investigation by the Transit Authority after a video showed one of their officers involved in the encounter.

The crowd celebrated the boy’s release by jumping, chanting and hugging each other.