A lawyer for New York's attorney general Tuesday told a state judge Exxon Mobil Corp. used two sets of books to hide the true cost of climate change regulations from investors, while an attorney for the oil major assailed the claims as false and politically motivated.

The lawyers' opening statements kicked off a long-awaited trial in a civil lawsuit filed by the attorney general last year accusing Exxon of defrauding investors out of up to $1.6 billion.

The trial, expected to last up to three weeks, will take place before Justice Barry Ostrager in Manhattan Supreme Court without a jury and could feature testimony from Rex Tillerson, who served as Exxon chief executive officer and U.S. Secretary of State.