Ukrainian President Volodymyr Zelensky says he has visited troops near the town of Pokrovsk, where the fiercest front line battle between Russia and Ukraine is currently taking place.

Zelensky posted photos showing him meeting personnel at a command post in the Dobropillya sector, some 20km (12 miles) north of Pokrovsk in the Donetsk region.

Kyiv's top military commander, Oleksandr Syrskiy, said on Monday that Ukraine was increasing pressure on the Dobropillya front to force the enemy to disperse its forces and make it impossible to concentrate their main efforts in the Pokrovsk area.

Russia has been trying to seize Pokrovsk - a strategic frontline town and logistic hub - for over a year.

Although it has taken them months to approach the town's borders, Russian soldiers have now infiltrated it and on Friday, Zelensky said Russia had amassed 170,000 troops on its outskirts.

Both Ukraine and Russia continue to issue claims and counter claims on the situation in and around Pokrovsk.

Capturing Pokrovsk could give Moscow access to the rest of Donetsk, including the towns Kramatorsk, Slovyansk, Kostyantynivka and Druzhkivka - the so-called fortress belt.

Gen Syrskiy acknowledged his troops were withstanding the pressure of a multi-thousand enemy grouping but denied they were encircled. Meanwhile, Russian military bloggers claimed 90% of Pokrovsk was under Moscow's control.

Unverified videos posted on social media show instances of close quarter combat, drone attacks and street battles there.

The US-based Institute for the Study of War (ISW) said that Russian forces were operating with increasing comfort within the town, which once had a population of 60,000 but has now been almost entirely emptied of civilians and largely destroyed.

Further east, Moscow's troops are also reportedly targeting the town of Myrnohrad, which would put Ukrainian soldiers at risk of encirclement.

Intense drone activity has cut off many logistics routes, making evacuations and the supply of ammunition and vehicles near impossible.

On Monday, Zelensky said Russia had had no success in Pokrovsk in recent days but acknowledged that things were not easy for Ukrainian forces in the area.

He added that a third of all front line clashes were happening in Pokrovsk, and a half of all glide bombs used by the Russians were launched at the town. Earlier last week the Ukrainian president said that Moscow's troops in the area were outnumbering Kyiv's eight to one.

Some Ukrainian commentators have criticised the government's efforts to continue to defend Pokrovsk, arguing that troops were being put at risk.

Zelensky said: This is our country, this is our East, and we will certainly do our utmost to keep it Ukrainian.

Russia now controls 81% of the Donetsk region and 99% of neighbouring Luhansk, which collectively make up the Donbas.

However, its progress along the front line has been grinding and occupying the heavily fortified towns in northern Donetsk could come at a huge cost of both manpower and resources.

A large-scale drone attack overnight Monday targeted the southern port of Odesa on the Black Sea, damaging industrial facilities, causing fires, and affecting the local power supply. At least 15 civilians were killed and 44 injured in combined drone and missile attacks across the country at the weekend.

Ukraine continues to retaliate, predominantly using drones to target industrial sites across Russia and border regions. Kyiv claimed responsibility for attacks on a petrochemical plant in the Bashkortostan region and a refinery in the Nizhny Novgorod region.