Loan default notices filed by U.S. banks against homeowners were up 33 percent last month, the largest monthly increase since 2007.

RealtyTrac, which tracks attempts by lenders to seize homes when loans are not repaid, said Thursday new foreclosure filings are at a nine-month high and there has been a 7 percent increase from the previous month.

The latest RealtyTrac report shows in August one in every 570 U.S. homes had a foreclosure filed against it, with the southwestern state of Nevada having the highest foreclosure rate.

The report's authors say the spike signifies that banks are starting to address a backlog after much foreclosure activity was halted late last year, when reports surfaced that lenders were automatically authorizing actions without reviewing case files.

One effect of the global financial crisis has been a surge in the number of people who can not repay their home loans, leading banks to seize the property. Lenders then sell the properties in the hope of recovering the money they loaned to the homeowner who defaulted.