(Reuters) -U.S. grocery chain Kroger ( KR ) countersued rival Albertsons ( ACI ) on Tuesday, escalating a legal fight between the two companies following the demise of their proposed $25 billion merger that was blocked by courts.

Albertsons ( ACI ) terminated its $25 billion bid to merge with Kroger ( KR ) in December after the deal got blocked and sued Kroger ( KR ), alleging a breach of contract that led to the deal's demise.

The formal termination ended a two-year effort by the grocery chains to combine. Regulators had noted that the deal would lead to higher prices for shoppers.