Russia, Uzbekistan and Tajikistan started trilateral military exercises in the Khatlon region of Tajikistan, near the Afghan border, on Thursday.

The drills that take place at the Kharbmaidon training ground involve 1,800 Russian soldiers and 420 units of military hardware, Russia’s Defense Ministry said on Monday as quoted by Reuters.

Quoted by Reuters, Tajikistan’s Defense Ministry said in its statement that the drills would involve more than 300 armored vehicles, 25 combat and transport helicopters, and an undisclosed number of fighter and bomber jets as well as artillery.

Russia is also carrying out drills in Uzbekistan, another former Soviet republic bordering Afghanistan, this week. For the Uzbek exercise, Moscow said on Thursday it would even deploy four strategic bombers.

This comes as the security situation in Afghanistan remains concerning amidst the withdrawal of foreign troops from the country. Moscow fears that could destabilize its southern defensive flank and push refugees into its Central Asian backyard.

Russia has increased arms and military hardware supplies to Uzbekistan and Tajikistan amid fighting in Afghanistan, Interfax news agency quoted Russian military chief of staff, Valery Gerasimov, as saying on Thursday.