US Treasury Sec Lew: By our standards we have a lot of work to do on economy

Treasury Secretary Jack Lew told CNBC on Wednesday that the U.S. is leading the global economic recovery, despite having "a lot of work to do" by our own country's standards.. His comments come as the U.S. faces rising geopolitical tensions between Ukraine and Russia. Lew last spoke to "Squawk Box" in January from the World Economic Forum in Davos, Switzerland.