WASHINGTON (AP) _ Independent Counsel Lawrence E. Walsh's Iran-Contra investigation cost more than $38 million through last September, according to a congressional report released Thursday.

The General Accounting Office reported that Walsh spent nearly $3.1 million in the six-month period that ended Sept. 30. A previous GAO report reported Walsh's probe cost some $35 million since it began in December 1986.

The GAO also reported that Arlin M. Adams, an independent counsel investigating wrongdoing by former Housing and Urban Development officials, spent $8.8 million through June 30, 1992.

The figure included $4 million spent in the six months ended last June 30 and $4.8 million reported previously by the GAO.