WASHINGTON (CNN) -- Attorneys for Vice President Cheney's former chief of staff Lewis "Scooter" Libby have decided against filing a motion for a new trial and plan instead to challenge his convictions on appeal, according to documents filed Friday in Federal court.

"Mr. Libby intends to raise in the court of appeals substantial issues of law on appeal of his conviction, including issues that may result in the granting of a new trial," defense counsel wrote in a notice filed in the case.

They faced a Friday deadline to file a motion for a new trial in district court. Such a move would ordinarily be accompanied by arguments establishing a basis for judge Reggie Walton to rule in their favor.

"However, defense counsel's review of the record leads us to conclude that the issues were adequately presented" at trial, the lawyers wrote. Libby, who resigned in 2005 as Cheney's top aide, pleaded not guilty to a five-count indictment, and last month was convicted of four counts involving obstruction, perjury and making false statements.