Sweden asked India on Thursday to clarify how the weapons wound up in Burma after it was revealed the Indian army had purchased them, Trade Minister Ewa Björling told the Swedish parliament.

Björling said the Swedish Agency for Non-Proliferation and Export Controls (ISP) had informed her that the weapons had come from India.

Pictures taken in Burma and published in Swedish media this week showed a Carl Gustav M3 anti-tank rifle and ammunition left behind by Burma government soldiers.

The weapon’s serial number is clearly visible in one of the photographs.

“One thing is clear… we are not in the business of supplying weaponry,” Salman Khurshid, Indian Minister of External Affairs, told reporters in Yangon.

“We will try to find out how this happened. It’s one weapon, isn’t it? In a very big world, one single weapon has been identified,” he said, adding that the Indian army will check its inventory as part of the probe.

The minister has met with Burma’s President Thein Sein and opposition leader Aung San Suu Kyi during his trip, holding discussions on energy, infrastructure and border issues.

According to a story published in Britain’s Independent newspaper, the Swedish weapons were used by Burmese troops in their fight against ethnic Kachin rebels in the country’s far north.

The rebels urged Burma’s military to end hostile operations in September after fighting broke out last year following the collapse of a 17-year ceasefire between the two sides, forcing tens of thousands of people to flee their homes.

Several rounds of talks aimed at resolving the conflict have been overshadowed by ongoing battles.

The European Union has had a weapons embargo against Myanmar since 1996.

On Wednesday, an ISP spokeswoman said it was “relatively unusual” for Swedish weapons to end up in the hands of third parties.