Embattled American bookseller Borders is undergoing more upheaval, with directors Edna Medford and Michael Weiss leaving the board.

Five of the remaining eight directors have also announced they are to leave, although they will wait until the retailer has found replacements before they go.

Borders plans to hire a search firm to find qualified candidates.

In February the retailer appointed a new group chief executive, Ron Marshall, and this year it has eliminated six vice-president positions and 10 directorial roles across the group.