Bank of America Corp said it will lay off about 2,500 workers in Illinois and 1,500 in Michigan over the next two years in connection with its $21 billion purchase of LaSalle Bank Corp from Dutch bank ABN AMRO Holding NV.

The cuts are intended to help the second-largest U.S. bank save about $800 million by 2009. Following the cuts, Bank of America expects to employ about 8,000 people in Illinois and 2,500 in Michigan. It ended June with 195,675 employees.

We're buying LaSalle with the goal of growing the combined organization, spokesman Scott Silvestri said. The layoffs are a necessary first step toward meeting that long-term goal.

On September 14, Charlotte, North Carolina-based Bank of America won approval from the U.S. Federal Reserve to buy LaSalle. The transaction is expected to close in early October.

LaSalle has about $160 billion of assets, 411 branches, 1,500 automated teller machines and 1.4 million customers.

Adding LaSalle would give Bank of America about $1.7 trillion of assets, trailing Citigroup Inc, and more than 6,100 U.S. branches, nearly twice as many as any other bank.