The war continues on the air, on land, on the black sea… and beneath the ground.

A few days ago, the Kremlin's spokesman Dmitry Peskov said what everyone already knows: the peace process between Russia and Ukraine is completely stopped.

In the meantime, Russian forces continue to apply pressure all over the front, with the undermanned and under-equipped Ukrainian defenses doing their best to stop them.

In the northern Kharkov region, the critical stronghold and railway hub of Kupyansk is at play now, with Russian troops preparing to cross the Oskol River, while increased pressure is applied to the defender positions to the north of the city.

But the most distinctive part of the offensive operations so far is the fact that Russian forces have once again used a tunnel to advance deep into enemy positions.

The first time this tactic was used in this war was in Donetsk city of Avdeevka, the second time near Sudzha during the liberation of the Kursk region, and now, Russians have laid an entire underground artery starting from Pervyi Lyman.

Attackers move along the pipeline on electric scooters and stretchers.

The underground tunnel includes rest areas and supply points, because the journey to Kupyansk takes about four days (!).

Now, while this may sound like another piece of Russian propaganda, the underground advances were reported on by the respected Ukrainian Telegram channel 'Deep State', that has grown to be a fairly reliable news source. They write:

"The Russians have built an entire logistical artery. The entrances to the pipe are located in the area of Pervyi Lyman.

Specially designed wheeled beds and electric scooters, where height is allowed, are used for movement inside the pipe. The route to the vicinity of Kupyansk takes about 4 days, so special rest areas and food supplies have been made along the way.