A man and woman from Grey County are facing more than 70 charges after police say they tried to smuggle illegal weapons across the US border.

Police say the guns and ammunition were meant to be sold on the black market.

The Canada Border Services Agency (CBSA) stopped a couple and their two children on March 16 as they crossed into Canada across the Rainbow Bridge in Niagara Falls. The CBSA says it got a tip from Toronto police.

Police say they searched the couple's van and found six concealed handguns; a seventh handgun was allegedly found on the man.

According to police, there were also two inert hand grenades, ammunition, over-capacity magazines, and knives in the van. As a precaution after finding the grenades, officers briefly closed several lanes of the Rainbow Bridge.

Police say another 34 guns – including 20 handguns – and hundreds of rounds of ammunition were later seized in raids at the couple's home in Proton Station, north-west of Shelburne.

Donald Hare, 44, and Amanda Brent, 43, are now facing a combined 73 weapons and weapons-trafficking-related charges. Investigators also allege five guns smuggled into Canada by the pair were recovered at crime scenes in Toronto and Peel Region, including one used in an attempted murder.

Toronto police say they are still investigating, and more charges could be laid. Brent and Hare remain in custody and have a court date in Toronto tomorrow.

Police wouldn't say who was caring for the two children.

- With files from The Canadian Press