The Pentagon official in charge of military procurement has quit in what appeared to be the latest fallout from disclosures of delays and cost overruns in development of the Navy's $50 billion A-12 Avenger bomber.

John Betti, undersecretary of defense for acquisition, submitted his letter of resignation Wednesday to Defense Secretary Dick Cheney, saying only that he intends to "return to the private sector." Cheney accepted the letter with the "deepest regret" and thanked Betti for his "dedicated and successful efforts."A Pentagon report released last month linked Betti to the A-12 mess, which not only embarrassed Cheney and the Navy but prompted the Justice Department to launch a criminal investigation of whether money went to contractors General Dynamics Corp. and McDonnell Douglas Corp. for incomplete work.

According to the Nov. 28 internal report, the Avenger project was 18 months behind schedule and as much as $1 billion over budget.