SOFIA -- Russian aircraft have repeatedly used the airspace of NATO-member Bulgaria to deliver military equipment to Serbia, a joint investigation by RFE/RL’s Bulgarian and Balkan services shows.
In the most recent case known, an AN-124 plane flying from Russia to Serbia passed through Bulgarian airspace on March 3, coinciding with the delivery of parts for the Russian Pantsir-C1 air defense system.
It was at least the fourth delivery of Russian military equipment to the Balkan country via Bulgarian airspace in the past few years.
The Bulgarian Foreign Ministry did not confirm it had received a request to transport Russian military supplies through its airspace, telling RFE/RL there were no grounds for refusing "flights delivering trade supplies between sovereign states."
The ministry further justified the flyover by pointing out "that no restrictive measures have been imposed on Serbia with regard to defense-related products by the UN, the EU, and the OSCE."
Romania, another NATO member, in July 2019 refused to allow the transit of Russian military equipment to Serbia, invoking the Kremlin’s annexation of Ukraine’s Crimean Peninsula. Romania is the most direct route for Serbian-bound flights from Russia.
The Russian flight was rerouted through Bulgarian airspace, according to data from the Flightradar24 tracking service.
Bulgaria’s actions indicate it is "quite friendly to Russia and its intentions," Todor Tagarev, a military expert and former interim defense minister in 2013, told RFE/RL.
"From a political point of view, the Bulgarian government does not seem to be worried about the fact that Russia is helping to build serious capabilities, including intelligence and air defense, of a country west of our borders," he said.
In the last two years, Serbia has received deliveries from Russia of the Panzer-C1 antiaircraft missile system, T-72 tanks, and BRDM-2 armored off-road vehicles. Some of the equipment was donated by Moscow to Belgrade while other items were purchased.
The Russian plane making the July 2019 delivery returned to its destination via Hungary, Slovakia, and Poland. It is unclear what was on board.
Hungary confirmed that it had been notified of the passover, but did not have to give permission because the flight was operated by a civilian operator. Poland claims that it was not informed about a flight over its airspace containing military cargo.
'There Is No Control Mechanism'
Meanwhile, Slovakia told RFE/RL it authorized the passage of such a flight through its airspace because the permission was made by a Russian civilian operator and the shipment was described as a nonmilitary "vehicle."
The Bulgarian Foreign Ministry did not specify what information it received about the cargo of this or other flights which are supposed to have carried military equipment.
Tagarev said there is no mechanism for monitoring the cargo of such flights over Bulgaria.
"When a request is received from the [Russian] Foreign Ministry, it states what the load is, but there is no control mechanism. We are supposed to believe what they have told us,” Tagarev explained.
The European Commission told RFE/RL that EU countries decide for themselves whether to allow the transit of weapons over their territory.
However, when making such decisions, member states must also comply with European rules for control over the export of military technology and equipment, the commission said.
NATO has not commented on the transit of Russian military equipment through the airspace of allies. The U.S. State Department did not immediately reply to a request for comment.
Tagarev said Sofia's decision to allow the transit of Russian military equipment through its airspace makes Bulgaria look like a "weak link in the allied defense and security system."
"While this is not an immediate threat, at the very least it is a lack of more strategic and long-term thinking on our part and allowing Russia to develop relations with other countries through actions that are not friendly to us."
Tagarev said the possibility of modern Russian antiaircraft missile systems, including systems that could be used for reconnaissance purposes, is concerning.
"What is worrying is not a certain number of tanks or several MiG-29 aircraft. Serbia, as a sovereign country, has the right to develop its capabilities as it sees fit. What we should be worried about are precisely those systems that can also be used for intelligence -- be it radar systems or other means."