WASHINGTON (AP) _ The Federal Trade Commission's staff will recommend approving the merger of office supply giants Staples Inc. and Office Depot Inc., one of the companies said Thursday.

Staples said it was told by the FTC's staff that the plan by the two companies to sell 63 stores to third-ranked competitor Office Max Inc. alleviates concerns the Staples-Office Depot merger would create a monopoly,

FTC spokeswoman Victoria Streitfeld would not comment.

The five-member commission could vote as early as Friday on the merger between the nation's two largest office supply chains.

``We're optimistic that the FTC commissioners will rule in our favor,'' said Staples spokeswoman Susan Grieb Simon.

Staples, based in Framingham, Mass., announced last September it would acquire Delray Beach, Fla.-based Office Depot for about $3.5 billion in stock. The value of the deal has increased to about $4 billion.

The two companies had taken out newspaper ads promising their customers that ``when we join forces, our greater efficiency means even lower prices for you.''

But FTC said last month a combined Staples-Office Depot could control prices in markets in 18 states and the District of Columbia where they are the only office-supply superstores.

On a 4-1 vote, the commission decided to seek a court order against the merger, but decided to hold off when the companies' proposed selling some stores to Office Max, which is headquartered in Shaker Heights, Ohio.

In the deal, Office Max would acquire stores in key markets where it doesn't have a presence, including Baltimore, Washington, San Diego, Tampa-St. Petersburg, Fla., and Louisville, Ky.

Office Max also would acquire 14 stores in the Los Angeles area and stores in 11 other markets, boosting its total number of outlets to 638. Staples and Office Depot still would be left with more than 1,000 stores between them.

The merger is being closely watched by the retail industry for clues about how the government will regulate the proliferation of superstores.