CHICAGO (Reuters) - President-elect Barack Obama moved closer to filling a key spot in his cabinet on Tuesday as his transition team plotted a careful course to shaping the next U.S. administration.

A Democratic source said a conditional offer for the post of attorney general had been made to former Clinton administration official Eric Holder, making him the automatic front-runner for the nation's top law enforcement position.

In keeping with his decision to maintain a low profile during the transition period before he takes office on January 20, Obama spent most of the day in private meetings at a federal office building near his home in Chicago.