Chain store sales climbed higher in the latest period, but discounters fared better than department stores, extending a running trend into the new year, two reports showed Wednesday.

Instinet Research's Redbook Retail Sales Average rose 1.4 percent in the first two retail weeks of January compared with the same period last month, and the Bank of Tokyo-Mitsubishi (BTM) and UBS Warburg reported that U.S. chain store sales rose 0.7 percent during the week ended Jan. 19.

"Below-plan performance at department stores was offset by strength at discount stores," Redbook said.

Year-over-year sales in the week ended Jan. 19 rose 1.6 percent.

"Sales generally were mixed relative to plan for most retailers, with discounters' sales tending to be above plan for the week while department stores and general merchandisers' sales tended to be on-to-below plan for the week," BTM said.

Compared with the same week last year the index grew 3.8 percent, well above the prior week's 2.3 percent year-over-year gain.

The Redbook Retail Sales Average is a sales-weighted average of annual growth in same-store sales at discount, department and chain stores that report their results on a weekly basis.

The average is compiled from a sample of general merchandise retailers representing about 9,000 stores. Same store sales measure revenues at stores open at least a year.

The Redbook Average is released weekly by Instinet Research, a division of Instinet, a Reuters-owned electronic brokerage.

The BTM/UBSW Weekly Chain Store Sales Snapshot is compiled from seven major discount, department and chain stores across the country that report their weekly results.

Those stores include J.C. Penney, Sears, Target, Kmart, Wal-Mart, Federated Department Stores Inc. and May Department Stores Co. The BTM/UBSW index measures sales growth with the year 1977 equaling 100.

Reuters contributed to this report.