Spiralling conflicts in Syria and the Middle East have sparked a flurry of activity in Bulgarian arms factories not seen since the collapse of communism.

The small EU member specialises in the production of affordable, lightweight Soviet-style weapons.

While main customers include governments in Afghanistan and Iraq, the arms have also found their way into the hands of opposition fighters in Syria's bloody civil war.

At one of the country's factories, hundreds of kilometres (miles) from Damascus, in a region known for its cultivation of roses, workers expertly assemble grenades for RPG-7 rocket-propelled launchers on a conveyor belt.

"The orders are exceeding our capacity," Ivan Getsov, director of the VMZ Sopot plant in the south-central village of Iganovo, told AFP.

"We produced as much in the first quarter of 2016 as in an entire year and a half previously," he said.

The boom, which started a year and a half ago, "is driven by the conflicts in Syria and Iraq," Bulgarian security expert Tihomir Bezlov said.

More specifically, it coincided with an escalation in the Syrian conflict in 2014 when major world powers became involved, either supporting or opposing President Bashar al-Assad in his fight against rebel groups.

Last June, the United States was forced to admit that it was equipping Syrian rebels, after an American defence contractor died in a blast at an arms testing range in Bulgaria.

Meanwhile, Saudi Arabia -- another big Bulgarian customer -- has also acknowledged supplying weapons to anti-Assad groups.

Riyadh signed a big Bulgarian arms deal in 2014. Analysts say it is unlikely that Saudi Arabia would buy these weapons for its own military, which uses modern arms.

"The Saudi military generally, but not exclusively, uses Western, rather than Eastern bloc weapons," said Jeremy Binnie, the Middle East editor of Jane's Defence Weekly magazine.

In addition, evidence retrieved on the ground shows that large quantities of Bulgarian weaponry have ended up in the possession of the Islamic State group in Iraq and Syria.

Of 161 cartridges used by the jihadists, 47 had been made in Bulgaria, according to Conflict Armament Research, a British non-governmental group monitoring the movement of weapons and ammunition globally.

- Guns versus roses -

At VMZ, two workers wearing protective gear carefully handle gunpowder cartridges inside a special armoured booth.

It is a dangerous job: earlier this year, three people died in two separate explosions at its Arsenal factory in the neighbouring town of Kazanlak.

Some of the employees sport face masks against the acrid chemical smell filling the factory, nestled at the foot of the Balkan mountains.

VMZ, Bulgaria's only remaining state-owned arms firm, recently expanded its premises and has gone on a massive recruitment drive for the first time in three decades.

Once severely indebted, VMZ is now one of the impoverished region's biggest employers along with the larger, privately run Arsenal plant. Together, they provide around 15,000 jobs.

In fact, local growers of roses -- the other major industry in the area -- worry that they will not find enough seasonal workers to help them during the summer harvest, according to media reports.

While it cannot compete with large-scale exporters like the US, China and Russia, Bulgaria has become one of the leading medium-sized producers of small arms, according to several independent international research groups, including the Geneva-based Small Arms Survey.

- Ageing technology -

Its military expertise harks back to the communist era.

Under the Soviet Union's defence treaty known as the Warsaw Pact, Bulgaria developed a powerful arms industry with some 115,000 workers.

It exported around $800 million -- its Soviet-era value -- worth of weapons per year to other Soviet bloc nations, but also to pro-communist groups in Africa and the Middle East.

The downfall of communism in 1989 plunged Bulgaria's industry into disarray, stripping the workforce to a tenth of its original size.

However, the escalating violence in the Middle East in recent years has helped fire up sales again.

Exports jumped from 80 million euros ($90 million) in 2008 to 400 million euros in 2014, further soaring to 640 million euros last year.

Sofia insists that it respects all international arms embargoes.

"The goods have a clear certificate for end destinations. Bulgaria cannot be held responsible for what happens from there on," said Economy Minister Bozhidar Lukarski last week.

But analysts warn that the industry could soon face a major hurdle because of its rapidly ageing technology purchased during Soviet times.

"There's a chronic lack of investment and cooperation with Western firms, which keeps Bulgaria from modernising its production infrastructure," said Bezlov.

Bulgarian arms producers hope their booming trade will enable them to now modernise their equipment.