Romanian authorities say they will refurbish two of their frigates with state-of-the-art equipment, as the NATO member moves to modernize its naval fleet to counter Russia's presence in the Black Sea.

The defense ministry said the frigates, built in 1986, will be equipped with anti-aircraft and anti-naval missiles and special sensors, which will be integrated into a computerized system.

The operation will cost 839 million lei ($208 million) and it will be open to companies with at least five years' experience.

Romania bought the King Ferdinand and the Queen Maria, named after a Romanian royal couple, from Britain in 2003.

Romania has promised to hike spending in defense to 2 percent of gross domestic product in 2017 in line with NATO demands.