Unconfirmed reports emerged on Facebook earlier that children at Balby Central Primary School in Doncaster were told to stay inside the building while police dealt with an incident close by.
Eyewitnesses posted on social media that pupils had been told to remain in the school building as a 'person with a weapon' had been spotted at a shop nearby.
Youngsters were reportedly allowed to leave just before 5pm and nobody was believed to have been injured.
Parent Ashley Cowley posted on Facebook: "I was at the school to pick my children up.
"All of us were waiting outside the school gates when we were informed by other parents that there was a person with a weapon at the shop on the corner, not at the actual school.
"The headteacher came out and the school was told to keep the children inside until it was safe to let them out by the police.
"But nobody saw anyone or anything just police going towards the shop."
South Yorkshire Police has not released any details about the incident yet. The force has been contacted for comment.
Nobody was in when we rang the school.