"It's the president's summit," Pentagon press secretary Eric Ruff said, adding that Rumsfeld made the decision not to go.
Ruff corrected his earlier statement that Deputy Defence Secretary Gordon England would go in Rumsfeld's place.
"Who it will be from DoD (Department of Defence) is to be determined," he said.
Rumsfeld, who resigned under fire last week, also has dropped from his schedule a pre-summit meeting in Washington with German Defence Minister Franz Josef Jung, Ruff said.
Rumsfeld will remain in his post until his successor, former CIA chief Robert Gates, is confirmed by the Senate, as expected.

Copyright AFP (Agence France-Presse), 2006