Washington ( CNN ) -- The federal government is scrambling to find ways to comply with President Obama 's order to put more air marshals on flights after a botched Christmas Day airline terrorist attack , government sources have told CNN . Hundreds of additional marshals could be `` loaned '' from the Secret Service and U.S. Customs and Border Protection , a U.S. official briefed on the investigation said . Another source said marshals could be drawn from Immigration and Customs Enforcement . Additional federal air marshals are needed for high-priority international flights , with other law enforcement personnel filling in on key domestic flights , another source noted . There are already believed to be thousands of air marshals , though exact figures have not been made public . Interactive : Key dates linked to Nigerian terror suspect . `` There are discussions within [ Department of Homeland Security ] law enforcement agencies about adding to the capacity of the Federal Air Marshal program , '' a homeland security official said . Internal notices issued Monday and Wednesday by the Department of Homeland Security ask employees to step up to train as air marshals and to serve at U.S. diplomatic posts abroad . Obama said Tuesday that he had ordered `` concrete steps to protect the American people , new screening and security for all flights , domestic and international , more explosive detection teams at airports , more air marshals on flights and deepening cooperation with international partners . '' Some immigration agents have been previously trained to be air marshals in emergencies . CNN 's Abbie Boudreau , Deborah Fayerick , Jeanne Meserve and Scott Zamost contributed to this report .
President Obama wants more air marshals on flights . Effort comes after botched airline terrorist attack . Official : Hundreds of additional marshals could be `` loaned '' from other agencies . Some immigration agents have been previously trained to be air marshals in emergencies .