By Susan Heavey

WASHINGTON (Reuters) - U.S. financial regulators have decided how multi-million dollar severance packages for the departing chief executives of mortgage giants Fannie Mae (FNM.N: Quote, Profile, Research) (FNM: Quote, Profile, Research) and Freddie Mac (FRE.N: Quote, Profile, Research) (FRE: Quote, Profile, Research) could be limited.

The Federal Housing Finance Agency (FHFA), which has taken over the two government-sponsored enterprises, said it could weigh a variety of factors, including whether the executives had committed fraud or insider abuse, according to a notice posted to the agency's website on Friday.

The notice, which applies to any severed Fannie Mae or Freddie Mac employee, does not say whether FHFA Director James Lockhart would actually take steps to limit the payouts.

Fannie Mae Chief Executive Daniel Mudd and Freddie Mac chief Richard Syron are entitled to combined pay and bonus packages worth about $24 million (13.4 million pounds) as part of the government's plan to restructure the troubled companies.

The so-called golden parachute payments have drawn criticism from Democrats, including presidential contender Barack Obama who earlier this week said such a windfall was unacceptable and the government's failure to block the packages violated the public's trust.

Democratic Senators Charles Schumer of New York and Jack Reed of Rhode Island have also urged reconsideration.

Republican presidential nominee John McCain also opposes the severance packages, McCain's chief economic adviser Douglas Holtz-Eakin said.

"They're inappropriate," he told Reuters.