DAVOS: NATO Secretary General Mark Rutte on Thursday urged the United States to keep supplying Ukraine with weapons to fight Russia's invasion and said he was sure Europe was ready to pay the bill. Speaking at the World Economic Forum in Davos, the NATO chief said Europe must invest more in defence, ramp up arms production and take a bigger share of spending on Ukraine aid. **More to Read:** _Macron brings Trump, Zelensky together ahead of Notre-Dame ceremony_ His comments came after US President Donald Trump said earlier this week that the European Union should be doing more to support Ukraine. "On Ukraine, we need the US also to stay involved," Rutte said. "If this new Trump administration is willing to keep on supplying Ukraine from its defence industrial base, the bill will be paid by the Europeans, I'm absolutely convinced of this, we have to be willing to do that," he added. **Read this too:** _US judge to hear states’ bid to block Trump birthright citizenship order_ He said Trump was right to say Europe should be paying more to help Ukraine win the war as "it is a worldwide conflict, yes, but still Ukraine is closer to Europe than to the US." Asked to elaborate on his comments, Rutte told Reuters in Davos that if the US keeps supplying arms to Ukraine, "then it is only fair that Europe will, in terms of the financial burden of those deliveries, pay the highest burden". He did not put a figure on how much Europe would pay or say whether he had agreement from European leaders on the matter. Trump's envoy for special missions, Richard Grenell, weighed in remotely on the Davos panel, which included Rutte, taking a swipe at the NATO secretary general, who previously served as Dutch prime minister and has supported NATO's position that Ukraine will become a member of the alliance in the future. "The American people are the ones that are paying for the defence. You cannot ask the American people to expand the umbrella of NATO when the current members aren't paying their fair share - and that includes the Dutch, who need to step up," Grenell said. In the panel discussion, Rutte said it was vital Russia did not win as it could result in Russian President Vladimir Putin "high fiving" the leaders of North Korea and China. "We really have to step up and not scale back our support for Ukraine," the NATO chief said. "The frontline is moving in the wrong direction," he said.