American International Group (AIG) has fired two top executives who refused to co-operate with an investigation into the insurer’s accounting practices.

Former CFO Howard Smith and former Vice President Reinsurance Christian Milton were fired after invoking their Fifth Amendment right to silence, in conflict with a company policy that requires employees to co-operate with government authorities in company investigations.

AIG is under investigation by New York Attorney-General Eliot Spitzer, the Securities and Exchange Commission and federal prosecutors, partly over a reinsurance deal with reinsurer General Re which may have been used to bolster their financial reports.