Former Hiroshima Mayor Tadatoshi Akiba on Thursday urged Russian President Vladimir Putin not to use nuclear weapons in Ukraine, after the Russian leader put his nuclear forces on high alert following his launch of an invasion of Ukraine last month.

Akiba, who started a petition earlier this month demanding Putin and world leaders declare they will not use nuclear weapons in the Ukraine crisis, said at a news conference that Putin's actions have left atomic bomb survivors and many other people appalled.

He said the victims of the 1945 U.S. atomic bombings on Hiroshima and Nagasaki went through a "living hell" and "despicable reality they somehow managed to survive." He urged leaders of nuclear states to visit the two cities to learn about the damage a nuclear attack can bring.