WASHINGTON DC: The United States and Russia are pledging to abide by a treaty limiting strategic nuclear weapons that took effect on Monday, but foreign leaders and experts fear a new arms race may be looming.
Concern over a potential conflict with nuclear-armed North Korea is also growing following a series of bellicose statements between Washington and Pyongyang.
The Strategic Arms Reduction Treaty (New START) signed in 2010 requires the United States and Russia to have reduced the number of their deployed nuclear warheads to 1,550 each by February 5, 2018.
The State Department said Monday the United States has lived up to the deal and it has "no reason to believe" Russia has done otherwise.
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Russia for its part said it was committed to the treaty and would provide Washington with data on its strategic nuclear arsenal in "the near future."
The New START treaty calls for inspections and for the world's two leading nuclear powers to exchange data on their arsenals to verify compliance.
The treaty signed by president Barack Obama was aimed at ushering in a new era in US-Russian relations and promoting the goal of doing away with nuclear arms.
But those twin objectives appear distant and President Donald Trump has little room for maneuver with Moscow as he grapples with allegations his campaign may have colluded with the Kremlin to get him elected.
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The New START treaty, the State Department said, is "critically important at a time when trust in the relationship has deteriorated and the threat of miscalculation and misperception has risen."
Mistrust of Russian intentions was reflected on Friday in a Nuclear Posture Review released by the Pentagon that called for a revamp of the US nuclear arsenal and development of new low-yield atomic weapons.
While the document underscored the administration's concerns about North Korea, Iran and China, the focus fell largely on Russia.
"This is a response to Russian expansion of their capability and the nature of their strategy and doctrine," Defense Secretary Jim Mattis wrote.
Moscow denounced what it called the "bellicose" and "anti-Russian" nature of the new US nuclear policy, warning that it would take the necessary measures to ensure its own security.
German Foreign Minister Sigmar Gabriel warned of the dangers for Europe of a "renewed nuclear arms race."
"Signs that Russia is re-arming, not only conventionally but with nuclear weapons, are obvious," Gabriel said.
"We in Europe must begin new initiatives for arms control and disarmament."
But instead of developing new weapons, Germany's top diplomat called for "existing arms control treaties to be upheld unconditionally."
Rachel Bronson, CEO and president of the Bulletin of the Atomic Scientists, said the Nuclear Posture Review "is a spruced-up Cold War document, responding in dated ways to current threats."
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Among the greatest of the current threats is that of North Korea, and the standoff between Washington and Pyongyang has many uneasy.
"If you believe that nuclear weapons deter and bring peace and stability, then we should welcome North Korea," Beatrice Fihn, executive director of the International Campaign to Abolish Nuclear Weapons, said mockingly.
"There are no acceptable nuclear weapons to use," Fihn, whose organisation won the 2017 Nobel Peace Prize, told AFP.
"Any use will trigger a nuclear weapons conflict with catastrophic humanitarian consequences for civilians."
Alicia Sanders-Zakre of the Arms Control Association said she was worried by "a president who repeatedly boasts about the size of his nuclear button on Twitter" and his "loose talk about nuclear weapons."
The White House last week dropped its nominee to be ambassador to South Korea, Victor Cha, after he publicly criticised a potential preemptive strike on North Korea.
Eighteen Democratic senators also came out against what has been called a "bloody nose" strike against North Korea.
"We are deeply concerned about the potential consequences of a preemptive military strike on North Korea and the risks of miscalculation and retaliation," they said in a letter.
The senators noted that in a Senate Armed Services Committee hearing last week, expert witnesses found that "such a 'bloody nose' strategy carried extreme risks."