Washington: The United States and Russia exchanged criticisms on Monday following reports of President Joe Biden's decision to permit Ukraine to utilize U.S.-supplied longer-range missiles to target areas within Russia. This development raises concerns about escalating Moscow's ongoing conflict in Ukraine. According to Yonhap News Agency, U.S. officials have reiterated accusations against Russia for escalating tensions, particularly following the deployment of North Korean troops to the conflict zone. Meanwhile, the Kremlin has accused the Biden administration of exacerbating the situation. The New York Times reported on Sunday that Biden has authorized the use of Army Tactical Missile Systems for strikes inside Russia, marking a significant policy shift just two months before his departure from office. However, Washington has not officially confirmed this report. State Department spokesperson Matthew Miller stated during a press briefing, "When you look at the escalation of this conflict, it has been Russi a that has escalated the conflict time and time again. This includes the recent recruitment of over 11,000 North Korean soldiers now positioned on the front lines in Kursk, actively engaging in combat against Ukrainian forces." Miller further emphasized, "This is a significant escalation by Russia, bringing in an Asian military to a European conflict. As we have stated, and as the secretary has mentioned, our response will be firm, and those supporting Ukraine must also respond firmly."