Ukrainian President Volodymyr Zelenskyy says North Korean soldiers joined battles against his country's forces in Russia's western region of Kursk bordering Ukraine, and have already suffered losses.

Zelenskyy made the statement in a news conference in the Hungarian capital of Budapest on Thursday.

The president said over 11,000 North Korean soldiers are present in the Kursk region, where Ukraine has been conducting cross-border attacks. He said some of them joined the battles against the Ukrainian military.

As for reactions about North Korea's dispatch of its soldiers, Zelenskyy said while there are countries that reacted, there are countries that had no reaction.

He called for a strong response from the international community, insisting that North Korea may increase the number of its soldiers unless there are decisive decisions.

Meanwhile, Russian President Vladimir Putin suggested that Russia could hold joint military drills with North Korea. Putin did not deny the possibility of conducting exercises when he was asked about it at a conference on international affairs in the southern Russian city of Sochi on Thursday.

Referring to a comprehensive strategic partnership treaty the two countries signed in June, Putin pointed out that its fourth article allows for mutual military assistance if either country is attacked or in a state of war.