Russia has deployed 50 warplanes for exercises over the Black Sea as the US warned airlines that civilian flights could be shot down.
The Vladimir Putin-led country continues to flex its military muscles, with new footage suggesting it is building up an armed frontier near the border with the Ukrainian border.
On Saturday it was conducting aerial manoeuvres, including missile launches and bombings, according to independent Russian news agency Interfax.
It added that aircraft involved were Su-27SM and Su-30SM fighters, Su-24M and Su-34 bombers and Su-25SM3 attack planes.
Naval aircraft and helicopters and the Black Sea Fleet are also involved.
The move is only likely to add fuel to the fire amid ongoing tensions with former Soviet state Ukraine.
Meanwhile, the US is said to have voiced fears the provocative exercises could lead to passenger flights being caught in the crossfire.
Washington has warned pilots against flying near the growing war zone around eastern Ukraine, according to a report.
Malaysia Airlines Boeing 777 flight MH17 was previously shot down by pro-Moscow rebels in similar circumstances, resulting in the death of 298 people in July 2014.
“During the exercises, the planes will perform missile launches and bombardment of naval targets,” said Interfax.
It added crews from both the Russian air force and Black Sea Fleet will “perform tasks to accompany ship strike groups and actions as part of reconnaissance strike complexes while ensuring security in the Black Sea”.
It comes as up to 100,000 Russian troops are believed to have been moved to Ukraine’s border.
Interfax went on to say an Su-25SM3 attack aircraft squadron placed in Crimea seven years ago has been “relocated to the Ashuluk test site in the Astrakhan region”.
Earlier this week, Russian defence minister Sergei Shoigu said Moscow was carrying out significant exercises in response to NATO threats.
Russian state-owned TASS news agency reported that the US Federal Aviation Authority (FAA) had recommended American commercial aircraft avoid flying overhead the contentious zones.
In Ukraine, meanwhile, army commander Colonel-General Ruslan Khomchak warned against the formation of private militias as they could be open to exploitation from Russia.
“I request representatives of state authorities and local administrations to refrain from instigating the situation and sowing panic sentiments in society,” he was quoted as saying.
“I urge to refrain from shifting the emphasis by creating militarised formations that are not stipulated by law.”