Ukraine commander says challenges increase in war with Russia

(Reuters) -Ukraine's top military commander, Oleksandr Syrskyi, said on Saturday that Ukraine faced increasing difficulties in its fight against Moscow's invasion as Russian forces advance and North Korean troops prepare to join the Kremlin's campaign.

Syrskyi, relating comments he made to a top U.S. general, said outnumbered Ukrainian forces faced Russian attacks in key sectors of the more than 2-1/2-year-old war with Russia.

President Volodymyr Zelenskiy said in a nightly address that Ukraine's military command was focused on defending around the town of Kurakhove -- a target of Russia's advances along with Pokrovsk, a logistical hub to the north.

He decried strikes on civilian targets and urged European countries to provide more air defence systems.

Syrskyi, writing on Facebook, said he told General Christopher Cavoli, who heads the U.S. European Command: "The situation remains challenging and shows signs of escalation.

"The enemy, leveraging its numerical advantage, is continuing offensive actions and is focusing its main efforts on the Pokrovsk and Kurakhove directions", Syrskyi said.

Russian forces, intent on capturing Ukraine's eastern Donbas province, made up of the Donetsk and Luhansk regions, have been regularly capturing new villages as they move towards Pokrovsk.

Ukraine's general staff, in a late evening report on Saturday, said 40 armed clashes had occurred around villages near Kurakhove.

Both Ukrainian and Russian military bloggers on Friday said Russian forces sought to encircle the city.

The United States, Western European countries and Ukraine say that North Korea, which entered a mutual defence pact with Russia in June, has sent troops to its ally.

"We have numerous reports of North Korean soldiers preparing to participate in combat operations alongside Russian Forces," Syrskyi said.

Zelenskiy has said 11,000 North Korean soldiers have arrived in Russia, specifically in the southern Kursk region, where Ukrainian forces staged a large incursion in August.

Both Zelenskiy and Defence Minister Rustem Umerov said this week that North Korean soldiers had already been involved in combat there.

The United States has been by far the biggest contributor of aid and arms to Ukraine, though Donald Trump's victory in the presidential election has raised questions about future policy.

Zelenskiy was among the first leaders to congratulate Trump after his victory on Tuesday. The Ukrainian president described his telephone conversation with Trump as "wonderful" and said contacts would continue.

(Reporting by Ron Popeski and Oleksandr Kozhukhar; Editing by Cynthia Osterman)