Two dozen arms control advocates have urged President Joe Biden to use next month’s G7 summit in Hiroshima, which was hit by the first US atomic bombing of World War Two, to reaffirm a US commitment to nuclear disarmament and readiness for arms control talks with Russia and China.

The advocates, including several former senior US arms control officials, made their appeal in a letter sent to Biden on Wednesday that has not been made public, but was reviewed by Reuters.

The May 19-21 summit in the Japanese city “creates an historic opportunity for you to acknowledge the horrors of nuclear war,” advance the goal of nuclear disarmament, and pledge “concrete steps to prevent a new arms race,” they wrote to Biden.

The White House did not immediately respond to a request for comment.

The appeal comes amid rising concerns over the suspension of New START, the last US-Russia nuclear arms limitation pact, China’s expanding nuclear stockpile and Tehran’s intensified uranium enrichment following the 2018 US repudiation of the 2015 Iran nuclear deal.

The letter urged Biden to deliver an address at the G7 summit acknowledging the “long-lasting human suffering” caused by the 1945 US atomic bombings of Hiroshima and Nagasaki, and the “catastrophic devastation” a nuclear war would cause “on a global scale.”

Biden should reiterate his readiness for talks with Russia on unfreezing New START, concerns with China’s nuclear buildup and his invitation to Beijing for a dialogue “at any level” on reducing the risk of miscalculation, the signers said.

He also should “create the conditions for progress on disarmament and head off a new arms race” by urging China, Britain and France to freeze their nuclear arsenals for as long as the United States and Russia maintain New START limits on their stockpiles, they said.