The US is seeking a clear explanation from Ukraine about Kiev's surprise attack on Russia's Kursk province. (Source: AP)

On August 13, TASS news agency quoted Russia's First Deputy Permanent Representative to the United Nations (UN) Dmitry Polyansky as saying that Ukraine's attack on the Kursk region was a clear sign that Kiev had chosen escalation and increased hostilities.

“This is the best counterargument to all our international partners who have stated that Kiev is moving towards a peaceful solution to the Ukrainian crisis,” he said.

According to the Russian diplomat , the attack on Kursk is "a move that Ukraine will certainly deeply regret".

In addition, Moscow also criticized Ukraine's Western allies at the United Nations Security Council (UNSC) for not condemning this attack campaign.

Russia has convened an informal meeting of the UN Security Council over Ukraine's offensive in Kursk, but Kiev's allies - including the US, France and Britain - have firmly backed the eastern European country and made no mention of the operation.

Russia has also accused Ukrainian forces of killing civilians and questioned the purpose of the cross-border attack.

Meanwhile, on the same day, US State Department deputy spokesman Vedant Patel stated that Washington was not involved in any aspect of the planning or preparation for the Kursk attack.

Reuters news agency also quoted White House spokesman Jean-Pierre as saying that the US was not informed in advance by Ukraine about Kiev's plans to launch the operation.

According to Ms. Jean-Pierre, Washington is seeking a clear explanation from Kiev about the goals of this sudden invasion.

Also on August 13, TASS quoted journalists from the White House press pool as saying that US President Joe Biden receives reports on the situation in Kursk every 4-5 hours, calling Ukraine's attack on Kursk a "real dilemma" for Russia.

Last week, Ukraine sent thousands of troops across the border and attacked Russia's Kursk province. Kiev claimed to have captured 1,000 square kilometers of territory in the area and taken control of 76 settlements, while Moscow said the Eastern European country had taken control of 28 settlements.