Dozens of residents from the city of Miami, Florida lined up outside City Hall on Saturday, holding their guns.

They will be donated to Ukraine through a gun buyback program called Guns 4 Ukraine, run by the local city council.

In exchange, residents received a gift card valued at up to $150, depending on the type of gun.

The program in total collected 69 guns in four hours, with firearms ranging from AK-47 style assault rifles to fully automatic AR-15s to homemade 3D-printed plastic guns.

The event was launched amid the nation's growing concerns over gun control after a spate of mass shootings in recent weeks, including one that killed 19 children at a Texas primary school in May.

A bipartisan group of senators agreed on a firearm safety bill last week, which could be the first potential breakthrough for gun law reform in decades.

It's never been done before:

The idea was sparked when the Miami police chief wanted to send defensive gear to Ukraine.

City of Miami Commissioner Ken Russell asked if they could also send guns — the police chief said it had never been done before.

"Obviously we're a municipality, we don't have international gun trade ability or jurisdiction," Commissioner Russell said.

They checked with the city lawyers and the state department and they found a way to do it.

Commissioner Russell introduced the initiative as a resolution at the city commission and it was accepted overwhelmingly.

Then they found a local exporter with a licence to sell guns to Ukraine and created the gun buyback program.

"Any resident who had a gun lying around the house that they didn't want could bring it, no questions asked," Commissioner Russell told the ABC.

"We would receive the gun, check it in, make sure it was safe... and then they would receive a gift card and be on their way."

Gun owners tell their stories:

Ken Russell was pleased to see the program welcomed.

"We thought this is something we could do at the city level to make a little difference, not only on the epidemic of gun violence, but also maybe to help Ukraine out a little bit," he said.

Commissioner Russell said several people drove from far away to take part in the program, and despite their no-question policy, many residents told stories related to their firearms.

He said one lady told him that her husband, a veteran who collected guns, was now going through Alzheimer's disease, which made her worry about having guns in the house.

"Another woman was divorced and her husband left the guns, and she had kids in the house and she didn't want them there," he said.

"There was just no real normal, safe place to take them, so this gave [her] an opportunity."

Commissioner Russell said the program was not an "Anti-gun" campaign, but about responsible gun ownership.

He said each donated gun would go through several checks to ensure the guns were safe to use and suitable for war in Ukraine.

"And so out of the [69 guns] there, if we can send a couple dozen over to Ukraine, we're very confident that it will be well received."

Story By | Rachel Hayter & Wing Kuang