Two men, initially pulled over on Hwy. 401 Friday because of a loud muffler, were arrested in a dramatic takedown after a police officer noticed a gun inside the car.

An OPP officer pulled over a green Volkswagen Passat around 3 a.m. Friday because the vehicle had a noisy muffler.

After approaching the car, the officer reportedly noticed the passenger had a handgun.

The OPP Guns and Gangs Unit, K-9 Unit and Toronto Police Emergency Task Force were all involved in the takedown after the officer called for backup.

"A lot of criminals are using our highways, bringing things across the border and going from place-to-place. They have to use the highways," OPP Const. Dave Woodford told CTV Toronto.

"So there is a lot of criminal activity on our highways and our officers are trained on any routine stop to be aware all the time. There's no such thing as a routine stop."

Toronto police blocked all lanes of the highway for about an hour as the suspects were arrested.

Two Toronto men, ages 24 and 28, were charged. The 28-year-old passenger faces a number of gun-related offences, while the driver faces traffic and liquor charges.