NEW YORK (AP) _ Buyout specialist Kohlberg Kravis Roberts & Co. today withdrew its $5.03 billion offer to acquire Kroger Co., saying it was disappointed the supermarket chain had rejected the proposal.

In a letter to Cincinnati-based Kroger, Kohlberg said, ''We find it difficult to understand that the board acted on matters of such importance to stockholders without the benefit of meeting with us ... We can only conclude that the board has decided the company is not for sale at any price. ''

Kohlberg said it did not anticipate making any further proposals.

A week ago, New York-based Kohlberg sweetened its bid for the nation's second-largest supermarket operator to $64 a share in cash and securities. The bid was competing against a $55-a-share offer from Maryland's Haft family, which began the contest last month.

Although analysts said Kroger managers might be pressured to accept Kohlberg's latest offer, the grocer last week began laying off employees as part of a restructuring plan designed to fend off the two unwanted suitors.

Some 300 positions were eliminated at Kroger headquarters, and the company also has announced plans to sell off certain assets.

As part of its restructuring, Kroger plans to distribute a special dividend of $40 in cash plus notes and stock for each Kroger share. In its letter to the board, Kohlberg said the financial community had valued the Kroger restructuring at $53 to $56 a share.

On Wall Street, trading in Kroger shares was halted temporarily. The last sale of Kroger stock was at $57.50 a share on the New York Stock Exchange, down 12 1/2 cents from Monday.

The buyout firm hinted it might have been willing to improve its offer if it had an opportunity to meet with the board.

''We are perplexed that the board found our proposal to be inadequate,'' the letter said, adding that Kohlberg was not even asked ''if we were in a position to improve'' the bid.

The Haft family, which controls Dart Group Corp. and has a reputation as corporate raiders, last week offered to help Kroger fight the Kohlberg bid by proposing to provide additional equity for Kroger's restructuring.

The 105-year-old Kroger has 170,000 employees and 52,000 shareholders. The company's main businesses are its supermarkets and convenience stores.