WASHINGTON (Reuters) - The U.S. Treasury said on Monday it would borrow more during the October-December period than it had previously estimated.

The Treasury said in a statement it expects to borrow $188 billion through credit markets during the period, up from an initial estimate of $182 billion.

The department said it expects to issue $56 billion in net marketable debt during the first quarter of 2017.

Additional details of Treasury's quarterly refunding will be announced at 0830 EDT (1230 GMT) on Wednesday.

(Reporting by Lindsay Dunsmuir; Editing by Andrea Ricci)