MERRIMACK, N.H. — Police in Merrimack, N.H., have issued high school students a warning to be careful playing the squirt-gun game “assassins,” after a student got into a minor car crash.

According to the game rules, students pay $5 each and are assigned a target to track down, using the squirt gun. They also have to avoid the person assigned to squirt them.

But on Wednesday, police said one student backed into another student’s vehicle during the game. Two students had blocked the driveway of a target. The targeted student then backed into one of the cars to try to avoid being hit.

No one was hurt, but police said charges are pending.

“The incident was a serious error in judgment and the involved parties are extremely lucky that no one was seriously injured during the collision,” the police department said in a statement on its Facebook page.

Merrimack High Principal Kenneth Johnson said he won’t support the game because it’s easy to see how students could take it too far.

“It’s highly organized,” Johnson told the Nashua Telegraph. “I think the kids who choose to participate have raised it to an even higher level. This seems to come up about this time every year.”