KYIV, Ukraine (AP) — Russian President Vladimir Putin acknowledges that what he calls his “special military operation” in Ukraine is taking longer than expected. When asked Wednesday about how long the war is taking, he responded: “Of course, it could be a lengthy process.” Russian troops invaded Ukraine more than nine months ago and unleashed fighting that has displaced millions from their homes, and killed and injured tens of thousands of people. Putin hailed his forces’ occupation of Ukrainian territories as a major achievement. He said his country’s nuclear weapons serve as a deterrent to escalation. Putin has periodically hinted at his potential use of nuclear weapons. Also, fresh signs emerged that Russian officials are strengthening border defenses.