BOULDER - Boulder City Council voted unanimously Tuesday night at a third meeting to ban the sale and possession of assault weapons, bump stocks and high-capacity magazines within city limits.

Several amendments were discussed at last week's meeting, including raising the age to buy firearms to 21 instead of 18 - and those amendments will be considered by the council at a later date, according to the city's Twitter account.

The ordinance defines "assault weapons" as semi-automatic firearms designed with military features to allow rapid spray firing for the quick and efficient killing of humans.

Those exempted from the ban would include law enforcement officials, military service members and holders of Federal Firearm Licenses, among others, per the city's Twitter account.

Gun control advocates in Boulder had urged the city council to pass the city's proposed ban on assault weapons, bump stocks and high-capacity magazines as soon as possible.

A group of people against the ordinance marched in Boulder ahead of the second vote last week. They openly carried long guns and police did not stop them - opting not to interfere with their right to assembly.

RELATED: Would Colorado’s firearm preemption law stop Boulder’s assault weapons ban?

People who own what city council called assault rifles prior to June 15 of this year have until the end of the year to do three things:

1 - Get rid of the gun

2 - Turn it into authorities

3 - Break the gun so it doesn't work

4 - Obtain a permit from the city

That permit will only be granted if a person passes a background check, isn't prohibited by law from owning a gun, can safely store the gun, would have the gun only on their property, and would immediately report the loss or theft of the gun.