Russia announced on Thursday it had started military exercises near the border with Ukraine in what is likely to be seen as a show of force in the standoff with Kiev and the West over Crimea.
Separately, the ministry said Russia had sent six Su-27 jet fighters and three military transport planes to ally Belarus, responding to a request prompted by joint U.S.-Polish exercises in NATO nation Poland, Interfax reported.
The Defence Ministry confirmed exercises had begun in the Southern Military District near the Ukrainian border, involving 8,500 artillery men. Pictures had appeared earlier on social media showing military vehicles on the move in the area.
The exercise includes a large number of artillery and Grad (Hail), Hurricane and Tornado multiple-rocket launchers, the Defence Ministry said in a statement on its website.
Also involved are Howitzers, Nona self-propelled artillery and Rapier anti-tank guns, and the aim is to improve cooperation with motorised infantry, tank, air-assault and marine units.
One of the exercises will involve firing at a conventional enemy up to 15 km (nine miles) away and half of the training will be at night, it said.
Drills were also being held in the Belgorod and Kursk regions, which border Ukraine, state-run news agency RIA cited the Defence Ministry as saying.
Russian forces' takeover of Ukraine's Crimea region has been bloodless but tensions are high there following the pro-Russian regional parliament's decision to hold a referendum on Sunday on joining Russia. Kiev and the West say the referendum is illegal.
Russia's armed forces also held much larger exercises in its Central and Western military districts last month, alarming the West and Kiev and causing concern in eastern regions of Ukraine where most people are Russian speakers.