In a telephone call with Obama, Putin expressed regret he will be unable to attend the summit May 18-19 because of "his responsibilities to finalize Cabinet appointments in the new Russian government," the White House said in a statement.
"President Obama expressed his understanding of President Putin's decision and welcomed the participation of Russian Prime Minister [Dmitry] Medvedev at the G8 Summit," the statement said.
During the telephone call, Obama and Putin "commemorated the occasion of Russia's celebration of Victory in Europe day, noting the historic war-time alliance between our two countries and underscoring their mutual commitment to strengthening the U.S.-Russian partnership," the White House said.
The two leaders "noted with satisfaction the concrete achievements of the last three years and expressed their commitment to enhance bilateral cooperation on the basis of mutual strategic interests."
Obama and Putin agreed to hold a bilateral meeting in June, when they will be in Los Cabos, Mexico, for the G20 Summit.
"The two presidents reiterated their interest in the sustained high-level dialogue that has characterized the re-set of relations, and the substantial progress of the last three years on issues like nuclear security and non-proliferation, Afghanistan, the [World Trade Organization], and increased trade and commercial ties," the White House said.