Believed to have been produced in 1949, the work was discovered in Sofia by a joint operation between Bulgarian and Greek anti-organised crime forces, co-ordinated by Europol, reported Bulgarian National Radio or BNR.
BNR sources have valued it at up to €50 million ($54 million). So far, few details have been provided about the work and what it depicts, however, Novinite news agency cited a report by Bulgarian National Television, claiming it was part of the personal collection of the late Romanian communist leader Nicolae Ceausescu — as evidenced by a stamp on its reverse.
The piece was seized alongside five paintings by other notable artists during simultaneous crackdowns on the trafficking of cultural objects in the Bulgarian capital of Sofia, and Athens and Crete in Greece. Four suspects, including three Greek citizens and one Bulgarian, are said to be in custody.
"This is an international operation with the participation of Europol, Greece and other countries," Bulgaria's chief secretary of the Ministry of Internal Affairs, Petar Todorov said, according to Novinite.
"To our great joy, we managed to establish and keep this painting and at the moment the expertise shows that it is an original."
Pollock was an influential member of the Abstract Expressionist movement of the 1940s and '50s, known for his "drip technique" of splashing or pouring liquid household paint on to large canvases. While some celebrated the primal and immediate nature of his works, produced using the force of his whole body, others criticised the seemingly random results.
His works represented a radically new approach, where works had no clear focal points of emphasis, or even identifiable parts. He died in 1956 aged 44 in a car crash while driving under the influence of alcohol.