Eleven people were missing after two merchant ships were struck off the Bulgarian coast on Tuesday in the latest sign of increasing spillover from the Ukraine war in the Black Sea.
Bulgarian Prime Minister Rumen Radev summoned the Russian ambassador after drones struck a Ukrainian-owned cargo ship, while another vessel was also hit and sank further north off the coast of the NATO and EU member.
Black Sea shipping has been hit by growing fallout from the Ukraine-Russia war in recent months.
Radev said the Ukrainian-owned cargo ship Chelsea 3 was "hit by three aerial drones", and shortly afterwards another ship was "struck" and sank.
"We lack solid, clear evidence to level accusations against any specific party; however ... logic suggests the outcome works to the advantage of the Russian Federation," he wrote, calling the attack "unacceptable".
The presidency later identified the sunken ship as the HS Dignity, a Guinea-Bissau flagged cargo vessel, and said it went down 17 nautical miles east of the Bulgarian town of Krapets.
"According to information we got from the rescue centre ... five people were rescued and 11 are missing. This is preliminary information," a spokeswoman for the northeastern region of Dobrich told AFP.
The ship was travelling between Algeria and the Romanian port of Braila with a crew of Syrian and Egyptian nationals, according to the Bulgarian interior ministry.
'Adjusting Deterrence'
Radev said all 15 crew members aboard the stricken Chelsea 3 -- seven Ukrainians and eight Azerbaijanis -- had been rescued.
It was hit 16 nautical miles east of the Bulgarian town of Byala, the interior ministry said.
Bulgarian Defence Minister Dimitar Stoyanov said it would be "illogical for the Ukrainians to strike their own ships".
"Under these circumstances, we assume the drones are Russian," he said.
This is the first time the country -- whose leader Radev is attempting to balance his Euro-Atlantic alignment with a more conciliatory approach toward Moscow -- has directly singled out Russia.
Speaking after a call with Radev, NATO chief Mark Rutte said the alliance would adjust its defences "as needed".
"We have already strengthened our posture along the eastern flank and will continue to monitor the security environment, adjusting our deterrence and defence posture," Rutte said.
EU chief Ursula von der Leyen condemned the attacks, calling them "another front of escalation of the Russian war in Ukraine".
Ukraine's Foreign Minister Andriy Sybiga also blamed Russia, denouncing what he called Moscow's "deliberate disregard for civilian lives and maritime security in the Black Sea".
"The Black Sea is a lifeline for global food security. Russia is attacking it to weaponise hunger and hold the world hostage," he posted on X.
Conflict Spreads
Amid mounting fallout from Russia's 2022 invasion of Ukraine, drone attacks have become increasingly frequent in neighbouring countries.
The conflict has also spread across the eastern Black Sea, with at least 45 merchant vessels attacked over the past 12 months in areas previously not listed as high risk, the maritime risk management group Ambrey said last month.
No strikes were recorded in the areas in the preceding 12 months, Ambrey said, adding that the increase was driven by attacks further from the coasts of Russia and Ukraine.
Last week, two commercial vessels were hit in the Black Sea off Bulgaria in an attack widely blamed on Russia, though Bulgaria said the circumstances were unclear.
Nine Syrians and one Egyptian remain missing.
That dual strike came a day after another ship caught fire and sank off the Romanian coast, killing one person and leaving another missing. Ukrainian President Volodymyr Zelensky said the ship was hit by Russian drones.
Two Bulgarian human rights groups, the Bulgarian Helsinki Committee and Bulgarian Lawyers for Human Rights, urged prosecutors to launch an immediate investigation into possible war crimes following the attacks.
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