NEW YORK AP – A battle broke out for control of Wachovia Friday as Wells Fargo signed a $15.1 billion agreement to buy the Charlotte, N.C.-based bank, while Citigroup and the federal regulators backing its earlier deal insisted that Citi’s takeover bid go forward.

The surprise announcement early Friday by Wachovia Corp. that it had agreed to be acquired by San Francisco-based Wells Fargo & Co. in the all-stock deal – without government assistance – upended what had appeared to be a carefully examined arrangement and caught regulators off guard.