What is happening in Ukraine's Sumy region according to recent announcements?

Russian President Vladimir Putin has announced that his troops have crossed into Ukraine's northeastern Sumy region, marking the first ground attack in this area since 2022. This represents a significant escalation in the ongoing conflict between Russia and Ukraine. However, Ukrainian officials in Kyiv have swiftly denied Putin's claims about a successful Russian incursion into the Sumy region. The contradicting statements from both sides highlight the ongoing information warfare that accompanies the physical conflict, leaving the actual situation on the ground uncertain.