Russia announced large-scale “attack” and amphibious assault exercises in and around annexed Crimea on Thursday as Western governments continue to sound the alarm over Moscow’s possible invasion of Ukraine.

More than 1,200 Russian airborne and artillery troops, as well as chemical and biological forces and 250 pieces of military hardware, will conduct combat firing exercises at the Opuk training ground in Crimea, according to the state-run TASS news agency.

Russia’s military will also deploy Mi-35 helicopters for amphibious assault and to provide air cover for attacking troops.

The military classified the two-day exercises as part of an “operational assembly of the forces’ command personnel.”

Russia announced the drills one day after the United States and Germany accused it of continuing to build up troops on the border with Ukraine.