President Vladimir Putin stated on Friday that deciding whether to use North Korean troops is Russia’s business and highlighted that Moscow has the right to secure its own safety, particularly if Ukraine wants to join NATO.

The U.S. disclosed on Wednesday that it had identified evidence of North Korea dispatching 3,000 troops to Russia, potentially to be deployed in Ukraine, a scenario the West seas as a significant escalation in the Ukraine — Russian war.

According to Ukraine’s military intelligence, the North Korean solders trained in Russia are now positioned in the Kursk region.

Putin, in a conversation with Russian state television, stated “When we have to decide something, we will decide… but it is our sovereign decision whether we will apply it, whether we will not, whether we need it.”

He noted that the West insists Ukraine must determine how to secure its safety, “with or without NATO.”

“The sooner they realise the futility of such an approach in relations with Russia, the better it will be for everyone, and perhaps, above all, for themselves,” Putin said.

During a June visit to Pyongyang, Putin and North Korean leader Kim Jong Un signed a comprehensive strategic partnership agreement.

Article 4 of the partnership specifies that, “If one of the Parties is subjected to an armed attack by any state or several states and thus finds itself in a state of war, the other party will immediately provide military and other assistance with all means at its disposal.”

While Putin did not deny U.S. allegations about North Korea sending troops on Thursday, he stated that it is Moscow’s decision how to implement its defense agreement with Pyongyang.