July 2 (Bloomberg) — Lewis “Scooter’’ Libby, an ex-aide to Vice President Dick Cheney, must go to prison while appealing his conviction for obstructing a CIA leak probe, a U.S. appeals court said. Libby may be behind bars within weeks under the decision by the U.S. Court of Appeals for the D.C. Circuit, which denied his request for release during his appeal. The decision will increase pressure on President George W. Bush to decide soon whether to pardon Libby, 56, as the former White House official’s supporters have urged. Libby was sentenced to 2 1/2 years in prison last month following his March 6 conviction of lying to investigators probing the 2003 leak of Central Intelligence Agency official Valerie Plame’s identity. U.S. District Judge Reggie Walton refused to let Libby stay out of prison during his appeal, saying that evidence of his guilt was “overwhelming.’’ Libby was convicted of obstructing justice, perjury and making false statements. He resigned as Cheney’s chief of staff upon being indicted in 2005.