Barack Obama is likely to announce plans next week to run for re-election and file campaign papers with the Federal Election Commission as early as Monday, a Democratic official said.
Filing with the FEC would allow Obama to start raising money for a 2012 campaign that is expected to break records in political spending.
The Democratic official stressed that no final decisions have been made about the timing of an announcement or filing.
Obama is in the middle of a budget battle with congressional Republicans and has focused his message in recent weeks on reducing US dependence on foreign oil and investing in innovation and education -- themes that are likely to feature in his bid to hold on to the White House next year.
At the same time, Obama has been defending US involvement in military operations in Libya.
Republicans are pressing Democrats to make deep spending cuts to tackle the US deficit, another topic that could play an important role in the 2012 campaign. The Republican field of presidential challengers is still wide open, however, and no formal announcements of presidential bids have been launched.
Obama is expected to avoid overt campaigning while his potential Republican opponents compete against themselves.
But he has started doing some fundraising events for his party in recent weeks. Formally announcing his candidacy would allow him to start filling his own campaign's coffers directly, too.