Ukraine's state-owned oil and gas major Naftogaz has inked its first deal with Azerbaijan's energy giant SOCAR to import natural gas via the Transbalkan route, it announced on Monday.

"For the first time, a test shipment of gas is being delivered through the Transbalkan route along the Bulgaria-Romania-Ukraine corridor," Naftogaz said in a statement on its website.

The Ukrainian company said the agreement was for a small volume of gas and did not specify timelines.

"This is a small volume but strategically important step that paves the way for long-term cooperation," Naftogaz CEO Serhiy Koretskyi was quoted in the statement.