Graphic Packaging's international unit said Tuesday it will close four plants by early next year as part of an ongoing restructuring effort to shave $90 million in costs by 2010.

The Marietta-based company said it will close its carton factories in Greensboro, N.C., and Richmond by the end of the year and a folding carton plant in Smyrna, Tenn., in the first quarter of next year.

Graphic Packaging also said it would close its Handschy ink and coating sales office in Grand Rapids, Mich., and an ink manufacturing plant in Indianapolis by the end of this month. Work from those operations will be transferred to other Handschy plants.

"We are working very aggressively to integrate assets, streamline our operating footprint and achieve announced synergies of a minimum of $90 million, all of which will ultimately make us a more successful company and better able to reduce debt and sustain our competitive market position," said David W. Scheible, Graphic Packaging International's president and chief executive, in a written statement.

"Our challenge, in what continues to be a difficult operating environment, remains to realign and optimize our increased scope of operations and make our packaging business the lowest cost in the industry."

Shares rose 5 cents or nearly 2 percent on the news, to $2.66 per share in early morning trading.