Johannesburg - Four men were arrested by Johannesburg metro police on a charge of possession of illegal firearms on Thursday morning, Chief Superintendent Wayne Minnaar said.
"An officer spotted a green Mercedes Benz driving recklessly on the N1 south, near William Nicol," he told News24.
"He gave chase and made them pull over. This was around 09:35. He ordered all four occupants to get out and put their hands on top of the car."
The officer then saw one of the men had a gun. He removed the gun and told the men to lie down before calling for back up.
When the other officers arrived, the men were searched and another firearm was discovered.
The serial numbers on both guns had been filed off.
The men were arrested and were expected to appear in court soon.