Former Soviet President Mikhail Gorbachev has pulled out of a meeting of Nobel Peace Prize winners that starts Friday in Hiroshima due to poor health.

Gorbachev, the last president of the Soviet Union and winner of the Nobel Peace Prize in 1990 for his part in ending the Cold War, has been told by doctors he can't travel internationally due to his condition, said Pio d'Emilia, a spokesman for the gathering. The specifics of his health were not immediately clear.

The annual World Summit of Nobel Peace Laureates brings past award recipients together to call attention to their achievements and work, as well as push the prize's overall message of human rights and nonviolence.

This year's gathering in Hiroshima will focus on nuclear nonproliferation.

Gorbachev, 79, was one of five peace laureates who signed a letter calling on U.S. President Barack Obama to attend this year's meeting and give fresh momentum to his call for a world without nuclear arms.

Obama, who won the peace prize in 2009 and will be in Yokohama this weekend to attend the Asia-Pacific Economic Cooperation forum summit, declined the invitation.

The Dalai Lama, in Hiroshima to attend the meeting, lamented how this year's prize winner, jailed Chinese dissident Liu Xiaobo, would not be there.

"Now here, Liu Xiaobo, you see, failed to come here. It is very sad," the exiled Tibetan religious leader said.

The Dalai Lama also said it was "very sad" that Myanmar's detained democracy leader, Aung San Suu Kyi, would not be able to attend.