Security in the Black Sea region: is Bulgaria the weak link in Europe's defense against threats from Russia?

Although security in the Baltic Sea and the threat of Russian provocation there are the subject of regular public debate, security in the Black Sea is a subject that sometimes gets less attention in the context of Russia's war in Ukraine even though the Black Sea is to a degree an active frontline in the war.

There are multiple reasons why the Black Sea's security is such a complex issue, but two incidents in recent days have highlighted just how precarious the situation there is.

On October 6, two cargo ships — the Alfa Watan and the Able — were struck by drones in the Bulgarian exclusive economic zone in the Black Sea.

The Alfa Watan sank, and its crew has not been recovered. Bulgaria conducted a search and rescue operation, which was called off on Wednesday morning.

The crew of the Able, which was damaged, was rescued by a passing Bulgarian ship. Two crew members were taken to the military hospital in Varna.

The day before, another cargo ship — the Royad Mammadov — was struck by a drone and sank off the coast of Romania. Two crew members lost their lives.

Multiple recent attacks on ships

These are not isolated incidents. In the past few months there have been multiple attacks on cargo ships carrying grain from Ukraine.

As a result, doubt is increasingly being cast on the belief that the western part of the Black Sea — the area off the coast of Bulgaria and Romania — is relatively safe.

"Тhe Black Sea front is clearly expanding, and we should no longer look only to the Baltic Sea as a potential avenue for escalation and aggressive actions," said Ruslan Trad, global security expert and non-resident fellow at the Atlantic Council's Digital Forensic Research Lab.

PM downplays drone attacks

Bulgarian Prime Minister Rumen Radev downplayed the attack on the ships, remarking that ships are constantly being sunk in the Black Sea and that Tuesday's drone attacks were "probably not the most serious incident."

Bulgaria's government called Tuesday's attack on the two vessels an "absolutely unacceptable violation of international law" but refrained from calling on Russia to end its war against Ukraine. 

Ukrainian President Volodymyr Zelenskyy, on the other hand, was unequivocal. He said that the Ukrainian military had assured Bulgaria that it was not responsible for the attack and pointed the finger squarely at Russia.

After a meeting of the National Security Council on Wednesday, a declaration was issued, which once again did not name the source of the threat in the Black Sea.

Radev stated that the cargo and the direction of travel of the ships "logically speaking" provide grounds for a hypothesis pointing to Russia but stressed that there is no concrete evidence. He also contradicted Zelenskyy, saying no such conversation had taken place.

Earlier he said that "if the war is not brought to an end in due time, it will continue to expand."

Similarly, Bulgaria's Foreign Minister Velislava Petrova said that "we need to support all possible diplomatic efforts to bring this war to an end."

The refusal to state clearly that it is Russian aggression that is putting the region at risk is not new for the Radev administration.

Is Bulgaria a 'weak link' in European defense?

For Rumena Filipova, chairperson of the Institute of Global Analytics, this is an example of how Bulgaria seems to be a weak link in Europe's defense against malicious influence from Russia and China.

"This weakness stems from the lack of a serious institutional response to hybrid attacks of any kind, the absence of appropriate measures and a general tendency to downplay incidents," she told DW.

"The perpetrator is not named explicitly, even though our partners in the European Union and NATO have already issued numerous warnings about what aggressive steps Russia could take against Europe," she said.

According to Filipova, the Bulgarian government's narrative about peace without actually specifying the conditions or consequences for Ukrainian and European security is a demonstration of its leniency toward Moscow and raises the question of Sofia's geopolitical orientation.

No smoking gun

One of the surviving members of the Able's crew has said that he believes it was a Russian strike because the ship was carrying Ukrainian grain.

Ruslan Trad says that the crew member's testimony is an eyewitness hypothesis, not hard proof.

"The logic of motive, however, points toward Russia, as it is the state systematically threatening navigation to Ukrainian ports," he told DW, adding, "Until more concrete data is revealed the most accurate phrasing is 'probable but unproven Russian responsibility' without excluding other possibilities."

Trad also pointed out that Bulgarian institutions lack experience in attributing maritime drones in Bulgaria's exclusive economic zone (EEZ). "When the system is uncertain, the safest institutional reaction is to say nothing until certainty is achieved," he said. "That is caution, but it is also a political choice."

Economic consequences

A direct military response or the triggering of NATO's Article 5, which guarantees collective defense in the event of an attack on any member state, should not be expected.

Bulgaria's EEZ in the Black Sea is not Bulgarian sovereign territory and, as such, the strikes on the ships in this zone do not constitute a direct attack on Bulgaria — or on Romania in the case of the Royad Mammadov.

Nevertheless, Ruslan Trad thinks these three incidents shatter the illusion that the western part of the Black Sea is a safe zone because of the distance between it and the frontlines in Ukraine.

"This will increase pressure for tighter maritime monitoring, anti‑mining capabilities, coordination between coastal guard services and intelligence‑sharing among allies," he said.

"The real effect will be a hardening of the shipping regime: stricter routing recommendations, higher insurance premiums and more difficulty hiring crews. Economic repercussions for local businesses can also be anticipated — imagine the impact on fishermen if they have to stay in ports constantly due to fear of further attacks. That is the intended effect of such strikes," he added.

Rumena Filipova believes that although Romania, Bulgaria and Turkey strengthened their Mine Countermeasures Black Sea Task Group at this year's NATO summit in Ankara, this is not enough.

She says there are far more substantial gaps in naval defense capabilities: "Modernization of Bulgaria's naval forces must be improved, much greater coordination — especially with Romania — is required. Yet, for more than a decade, Bulgarian authorities have downplayed or ignored the idea of developing joint naval defense forces and coordination, and that trend continues today," she said.

Turkey's leverage and China's role

Another question is how Turkey will react to recent developments. All three ships were owned by Turkish firms and some of the crew members were Turkish nationals. Turkish President Recep Tayyip Erdogan on Wednesday spoke to Russian President Vladimir Putin about the security of navigation in the Black Sea.

Trad notes that Ankara has several levers of influence in the Black Sea: control of the Straits under the Montreux Convention, the largest fleet in the Black Sea and its role as a mediator between Moscow and Kyiv.

"A realistic scenario is intensified diplomacy, coordination with Bucharest and Sofia, and pressure for safe navigation, probably within the existing trilateral anti‑mining cooperation. If it turns out that Turkish citizens were killed in a deliberate attack, Ankara's stance could become markedly tougher," he said.

Filipova thinks that Black Sea security is already being perceived as a core issue — not only for the region but for NATO as a whole.

In her view, there's not enough coordination between the countries in the region, which means that any response to threats does not come from a united front — something she feels has to change urgently.

Filipova says that China's influence in the region and how it's connected with Russia is another factor.

"We see not only the concrete military threat from Russia but also a subtler threat from China, which is less publicly discussed. But Beijing is trying to acquire strategic assets in ports, thereby gaining influence over both trade and critical infrastructure," she said. "Given that China and Russia cooperate closely, this constitutes a double threat for the Black Sea region."