US President Joe Biden reiterated on Monday that he was not announcing a change in US policy when he said on the weekend that Russian President Vladimir Putin "cannot remain in power". "I just was expressing my outrage. He shouldn't remain in power, just like, you know, bad people shouldn't continue to do bad things," Biden said in response to a question from CNN' s Kaitlan Collins at the White House. "But it doesn't mean we have a fundamental policy to do anything to take Putin down in any way," he added. Biden made the controversial comment at the end of an address in Warsaw. Mentioning Putin, the President said, "For God's sake, this man cannot remain in power". A White House official later said the line was not in Biden's pre-prepared speech. The White House and Biden have repeatedly tried to downplay the remark. The administration and allies say Biden wasn't calling for regime change to remove Putin from power. Rather, they argue that Biden was saying Putin cannot be allowed to exercise power over neighboring nations. "I was talking to the Russian people," Biden said on Monday when asked by Collins why he ad-libbed the line. "The last part of the speech was talking to Russian people," he added. "I was communicating this to, not only the Russian people but the whole world. This is ... just stating a simple fact that this kind of behavior is totally unacceptable. Totally unacceptable. And the way to deal with it is to strengthen and keep NATO completely united and help Ukraine where we can." Biden emphasized that he was speaking from the heart following a meeting with Ukrainian refugees in Warsaw. "I'd just come from being with those families," he said, adding, "I make no apologies for it." The President also dismissed the suggestion that his remarks might escalate the conflict in Ukraine. Biden said the suggestion that other leaders may take issue with his unscripted remarks during his address in Poland has not weakened NATO. "NATO has never ever, ever, ever, ever, ever been as strong as it is today," Biden said. The controversial comment came a day after Biden for a second time called Putin a "war criminal" . According to ABC News , Biden said, "The single most important thing that we can do from the outset is to keep the democracies united in our opposition and our effort to curtail the devastation that is occurring at the hands of a man who I quite frankly think is a war criminal." "I think it will meet the legal definition of that as well," he added. Friday’s comment marked the second time in recent weeks that Biden has called Putin a "war criminal", the harshest condemnation of Putin's actions from any US official since the war in Ukraine. "I think he is a war criminal," Biden told reporters the week before. Kremlin later spokesman Dmitry Peskov said the comment was "unacceptable and unforgivable rhetoric." Biden doubled down on his criticism of Putin a day later, calling the Russian leader a "murderous dictator" and a "pure thug". US Secretary of State Antony Blinken later said he personally believes war crimes have been committed in Ukraine. Related articles: Why Trump's Ukraine policies have US Jews worried Trump Admin. has set date for full ceasefire in Ukraine One dead in Ukrainian attack on Moscow Is Russia planning to attack another European country?