The Justice Department and Citigroup Inc. are locked in a high-stakes game of chicken, with the U.S. warning that it plans to file a lawsuit as early as next week related to Citigroup's alleged sale of shoddy mortgages in the run-up to the financial crisis, the Wall Street Journal reported on Saturday. Citigroup is offering less than $4 billion to resolve a long-running civil probe by the Justice Department over how the bank packaged mortgages into bonds and sold them to investors. The government has sought a figure closer to $10 billion. The two sides also remain far apart on the substance of the government's allegations with the bank arguing its pre-crisis conduct shouldn't warrant such a large sum.