Russia is mobilizing tens of thousands of troops and trying to drive Ukrainian forces from the territory it controls in Kursk province. (Source: Getty)

According to a source from the Ukrainian General Staff, from the initial area controlled by 1,376 km2 after the surprise attack in August, Ukraine now holds only about 800 km2. Russia has mobilized 59,000 troops to this area, including North Korean soldiers.

Kiev's attack on Kursk was intended to stop Moscow's offensive in eastern and northeastern Ukraine, forcing Russia to withdraw its troops.

However, Russian forces are still advancing steadily in the Donetsk region of eastern Ukraine at a speed of 200-300m per day. Currently, Russia has about 575,000 troops participating in the special military operation in Ukraine and is expected to increase to 690,000 troops.

In response, Ukraine has stepped up attacks on military targets deep inside Russian territory, including weapons depots and airports, thanks to the US easing of restrictions on the use of Western weapons.

In another development, Ukraine's Deputy Minister of Strategic Industries Anna Gvozdyar said Kiev is researching and developing "more than one" ballistic missile.

Although Ukraine has kept details of its missile program secret, The Wall Street Journal (WSJ) confirmed that Kiev officials have recently signaled that the new weapons could soon be put into use.

However, due to inadequate funding, Ukraine's missile program is questionable in terms of its actual effectiveness.

Previously, Russian President Vladimir Putin announced that the country's military had used one of the most modern hypersonic medium-range ballistic missile systems, Oreshnik, which no air defense system of the North Atlantic Treaty Organization (NATO) could intercept.