Russian fighter jets that made numerous low-altitude passes close to a US military destroyer in the Baltic Sea earlier this week observed all safety regulations, a Russian Defence Ministry spokesman said Thursday.
According to the Pentagon, the Russian Sukhoi Su-24 jets made "aggressive" flyovers on Monday and Tuesday in close proximity to the USS Donald Cook, with US media reporting that they flew as close as an estimated 10 metres from the ship.
A Russian military helicopter also flew a number of low-altitude circles around the ship on Tuesday, taking photographs as it flew, according to US media reports.
Russian Major General Igor Konashenkov rejected the criticism, saying the manoeuvres by the Sukhoi Su-24 jets were carried out during scheduled training flights over neutral waters in the Baltic, according to Russian state news agency TASS.
"Spotting the ship within the visibility zone, the Russian pilots turned their aircraft away from the vessel, fully observing the safety measures," TASS quoted Konashenkov as saying.
"The reason for such an aggrieved reaction from our US colleagues is, frankly speaking, incomprehensible to us," he added, according to Interfax news agency.
Echoing the Pentagon's earlier assessment of the manoeuvres, NATO chief Jens Stoltenberg on Thursday called Russia's behaviour "unsafe and unprofessional."
"We have seen substantial, significant increases in military activity along our borders," Stoltenberg told journalists in London. "And we have to avoid incidents, and accidents, and if they happen, we have to make sure they don't spiral out of control."
Stoltenberg says the issues of transparency on military activities and risk reduction will be addressed during a meeting between NATO ambassadors and their Russian counterpart on April 20 - the first to be held in nearly two years.
White House spokesman Josh Earnest on Thursday pointed to the Incidents at Sea Agreement (INCSEA), reached between the US and Russia in 1972, that calls on military aircraft to "use the greatest caution and prudence in approaching aircraft and ships of the other party" at sea.
Earnest said that the US raised their concerns with Russia via the US military attache in Moscow.
At the time of the incident, the USS Donald Cook was some 70 kilometres from a Russian naval base.