LOS ANGELES (AP) — Lenders stepped up action last month against homeowners who had fallen behind on their mortgage payments, taking possession of more homes and initiating the foreclosure countdown clock on many others.Completed foreclosures jumped 11 percent nationally in May from the previous month, with monthly increases taking place in 33 states, foreclosure listing firm RealtyTrac Inc. said Thursday.The monthly pick up reflects a rise in homes entering the foreclosure process last year. Many of those homes wound their way through the often lengthy process and ended up becoming bank-owned properties. Home repossessions, however, were down 29 percent from May last year, reflecting the long-term downward trend.Banks also started the foreclosure process on more homes last month.