USA: Despite a sluggish US economy and trillions of dollars in public debt, US Treasury Secretary Janet Yellen has traveled to Ukraine to meet President Vladimir Zelensky and other top leaders. Yellen said she wanted to highlight "the White House's close partnership in providing economic and budgetary support" to Kiev during her meeting with Zelensky, when an unannounced visit to the Ukrainian capital began on Monday. She echoed Zelensky's own remarks to US lawmakers during his visit to Washington, DC in December, saying that our support is not a "charity", but an "investment in global security and democracy". The official said that during the conflict with Russia, US support would last "as long as it is necessary". Also Read: Somalis fleeing drought must contend with cholera and malnutrition in Kenya Days before Yellen's visit, Washington announced an additional $12 billion in aid to Kiev, including a $2 billion arms package and an additional $10 billion to help with energy costs and the country's budget. He said on Monday that since last year the US has given about $50 billion in aid, a large part of which goes to weapons. Yellen acknowledged that Ukraine still had "enormous economic needs", she wrote while she was in Kiev, but argued that Washington needed to support "Ukraine's front line of defense against Russia". Kiev's "home front" must be "strengthened". Also Read: Former shah's son calls on the West to support Iranian dissidents Yet, despite his outspoken support for US leniency toward Kiev, the Treasury secretary also raised the country's economic woes, telling CNN on Monday that inflation is still "very high" and that the huge amount of US government debt Citing Yellen said the Treasury has been forced to take "extraordinary measures" to prevent a catastrophic default that, in a worst-case scenario, could result in the suspension of welfare payments to Americans and chaos in financial markets. He said Congress is on the verge of reaching the $31.4 trillion debt limit. Treasury bonds are the safest asset in the US, which has the "deepest and most liquid financial market," he said, adding that "preserving it is extremely important to avoid economic and financial catastrophe." Kiev has demanded increasingly powerful weapons from its foreign backers during its year-long conflict with Russia, and Washington has complied by providing a long list of state-of-the-art weapons, vehicles and ammunition. Also Read: Un makes an effort to reach a high seas treaty Despite recent elections showing declining US support for continued aid, Ukrainian officials have persisted in demanding more arms and money. President Zelensky warned that the US would "lose [its] leadership position" in the world if it should stop the flow of arms during a briefing last week, when asked about the enthusiasm.