German military authorities, and a German mine producing company, have unofficially confirmed that the DM-31 AVM (in Sweden called the FFV-028) manufactured by Bofors AB in Sweden and Dynamit Nobel in Germany, can be detonated by the presence of metallic objects. Sweden, Canada and the Netherlands also stock the FFV-028.
Canadian military authorities stated that the mine is activated by changes in the electromagnetic field around it and that the DM-31/FFV-028 mine may be set off by sweeping a metal detector over the mine.
The Dutch Ministry of Defence apparently believes the mine may not be compliant with the Ottawa Convention because of the
highly sensitive nature of its sensor.

Text below comes from Wikipedia :

The FFV 028 is a series of steel cased Swedish anti-tank mines that use electronic fuzes.
The mines are circular, with a large Misznay Schardin effect warhead in the center of the mine, with the fuzing and sensor electronics located in the dead space above the main charge.
The design of the mine dates from the 1970s and uses a magnetic influence sensor to detonate the mine, making it able to attack the full width of armoured vehicles. The mine can be laid either by hand or by a mechanical mine laying system.
Once the mine is emplaced, a pre-set arming delay of up to 60 minutes is initiated, after which the magnetic sensor activates and will trigger the mine if a target passes overhead. When the mine is triggered, a small clearing charge blows away any material that may have been on top of the mine, followed a fraction of a second later by detonation of the main explosive charge detonates.
The main charge creates an explosively formed penetrator which is capable of penetrating the belly armour of any tank currently in existence, and generates substantial secondary blast and fragmentation effects. The mine is blast resistant and has been upgraded to be resistant to advanced demining mine countermeasures.

The mine was ordered by the Swedish armed forces in 1982, where it is known as Stridsvagnsmina 6.
Subsequently, an order from Germany was placed for 125,000 mines in 1985. The Netherlands placed an order for in excess of 10,000 mines and associated mine laying equipment in 1985, with a second order for additional mines in 1989.

FFV 028 - Pre-production model
FFV 028 RU - Reusable version of the mine, which can be manually disarmed
FFV 028 SD - Version fitted with a ball-bearing based anti-handling device. The mine self destructs after between 30 and 180 days
FFV 028 SN - Self-neutralizing version of the mine, which disarms itself after 30 to 180 days, indicating its status by launching a red marking cylinder attached to a 0.5 meter long wire.
DM 31 - German version of the mine.

Diameter: 260 mm
Height: 100 mm
Weight: 9 kg (approx)
Explosive content: 5 kg (approx) RDX