President Barack Obama looks likely to order U.S. combat troops to withdraw from Iraq over a period of about 19 months -- a compromise between his campaign pledge and some commanders'' wishes, officials said on Tuesday.

A formal announcement is expected by the end of the week, marking a milestone in an unpopular conflict that overshadowed the presidency of Republican George W. Bush and helped Democrats retake Congress and the White House.

Obama''s decision fits with his intention to shift the United States'' military focus to Afghanistan from Iraq and to cut the U.S. budget deficit, partly by reducing war costs.

Obama was likely to come down somewhere between the 16-month timetable he advocated as a presidential candidate and fierce war critic, and a 23-month plan favored by some military commanders, an administration official said.

A second official said a 19-month compromise plan now seemed the most likely option.

"That''s the way the wind''s blowing," the official said.