Mitsui Construction Co. and Sumitomo Construction Co. said Wednesday progress is being made in their business integration talks but no specifics have been settled.

"Business integration talks have been smoothly under way" since the two firms agreed in principal Jan. 30 to form a comprehensive alliance to integrate business operations, Mitsui said in a brief statement. "But there has been no decision on what form the integration will take or the merger ratio so far."

Sumitomo issued a similar statement.