By Stoyan Nenov
SOFIA (Reuters) - A Bulgarian army bomb disposal team on Monday destroyed in a controlled explosion a device attached to a drone that landed on Sunday evening in the Black Sea town of Tyulenovo, the defence ministry said in a statement.
The army unit inspected the site and concluded that transporting the drone to another location with the explosives still attached would not be possible, the defence ministry said.
"We can certainly assume that it is related to the war that Russia launched against Ukraine," Defence Minister Todor Tagarev told reporters. "This war is inevitably associated with increasing risks to our security."
Tagarev did not provide more detailed information on where the drone came from and how it reached NATO member Bulgaria.
The tourist resort of Tyulenovo is situated 70 kilometres (43 miles) south of the Romanian border and across the Black Sea from Crimea, the peninsula annexed by Russia in 2014 and now a regular target of Ukrainian drone attacks.
Police cordoned off the area on Sunday evening and restricted public access to local restaurant terraces, Marian Zhechev, mayor of Shabla municipality of which Tyulenovo is a part, told Nova TV.
He said the drone had been found on rocks next to moored boats at Tyulenovo, describing it as an "aircraft with standard ammunition".
It was unclear whether the drone had fallen from the air or had been washed up by the sea currents.
Nova.bg web site quoted witnesses as saying that the drone was between 3 and 3.5 metres long.
Last week, fragments of a suspected drone were found in Romania, after a new Russian attack on Ukraine's Danube ports across the border.
(Reporting by Stoyan Nenov in Sofia and Ivana Sekularac in Belgrade; Editing by Toby Chopra, Gareth Jones and Alex Richardson)