The White House has sought to clarify remarks by US President Joe Biden who declared that the risk of nuclear "Armageddon" is at the highest level since the 1962 Cuban Missile Crisis. White House press secretary Karine Jean-Pierre underscored that there are no indications "that Russia is preparing to imminently use nuclear weapons". She told reporters Friday the US has seen no reason to adjust its own strategic nuclear posture and that Biden was just showing "how seriously" he is taking Russian President Vladimir Putin's rhetoric. Speaking at a Democratic fundraiser Thursday night, Biden warned that Putin was "not joking" when he talks about the potential use of tactical nuclear weapons or biological or chemical weapons. He added that Kremlin-backed forces were "underperforming" and said the US was trying to figure out Putin's "off-ramp" from the war. "We have not faced the prospect of Armageddon since Kennedy and the Cuban Missile Crisis," Biden added. US officials for months have warned of the prospect that Russia could use weapons of mass destruction in Ukraine as it has faced strategic setbacks on the battlefield, though Biden's remarks marked the starkest warnings yet by the US government about the nuclear stakes. Still, Jean-Pierre underscored that nothing has changed in US intelligence assessments that in recent weeks have shown no evidence that Putin has imminent plans to deploy nuclear weapons. Nikolai Sokov, a senior fellow at the Vienna Centre for Disarmament and Non-Proliferation who used to work at Russia's Foreign Ministry, told Euronews that he thought the probability of Moscow using nuclear weapons against Ukraine was "very, very low". Meanwhile, a spokesman for Ukraine's president said Volodymyr Zelensky would never ask NATO to launch a nuclear first strike to prevent Russia from unleashing its own nuclear arsenal. Zelensky's press officer Serhiy Nikiforov said on Friday the Ukrainian president's remark during a discussion at Australia's Lowy Institute didn't imply that NATO should launch a preemptive nuclear attack, but instead to act proactively with additional sanctions as it should have done prior to Russia's Feb. 24 invasion. Ukrainian presidential advisor Mykhailo Podolyak posted on Twitter that Zelensky's reference to strikes meant that the West should step up sanctions as well as military aid to Ukraine. In response to a question about what NATO should do to deter Russia from using nuclear weapons, Zelenksy told the Lowy Institute the alliance should "make it impossible for Russia to use nuclear weapons" through "preemptive strikes, so they know what will happen to them if they do". Russian Foreign Minister Sergei Lavrov seized on Zelensky's remarks, saying they confirmed the need for what Moscow calls its "special operation" in Ukraine. In an interview with the BBC broadcast on Friday, Ukraine's president said Russian officials had begun to "prepare their society" for the possible use of nuclear weapons in the war. In another report, the death toll from a missile attack on apartment buildings in Zaporizhzhia rose to 12 as more Russian missiles targeted the Ukrainian-held southern city on Friday. The Zaporizhzhia Regional Administration said Friday 21 people were rescued from the rubble of residential buildings that were hit with modified S-300 missiles. A dozen people remain hospitalized, including two children. Russia was reported to have converted the S-300 from its original use as a long-range antiaircraft weapon into a missile for ground attacks because of a shortage of other, more suitable weapons. Regional Governor Oleksandr Staruch posted on his Telegram channel that this was not random, but a deliberate strike on multistory buildings. He also said that — for the first time — Russian forces on Friday deployed Iranian-made Shahed-136 drones that damaged two infrastructure facilities in Zaporizhzha. The unmanned, disposable "kamikaze drones" are cheaper and less sophisticated than missiles but have proved effective at causing damage to targets on the ground. The Ukrainian military said most of the drones it shot down Thursday and into Friday were the Iranian-made Shahed-136. The weapons are unlikely to significantly affect the course of the war, however, the Washington-based Institute for the Study of War said. "They have used many drones against civilian targets in rear areas, likely hoping to generate nonlinear effects through terror. Such efforts are not succeeding," analysts at the think tank wrote. Also, the UN's top human rights body has voted to appoint a monitor to scrutinize reported rights abuses in Russia. The measure was approved by the 47-member UN Human Right Council in Geneva. It's the first time a special rapporteur has been appointed to investigate rights issues in a permanent member of the Security Council. "For years we've been witnessing a steady deterioration in the human rights situation in the Russian Federation, which has accelerated in recent months," said Mirk Bichler, Luxembourg's Ambassador to the UNHRC. "Recent draconian laws, aimed at stifling independent media and 'undesirable' organizations, harsh sanctions for anyone who questions the government, or the large number of people arrested in connection with demonstrations, are some recent examples of a systematic policy of repression." Since Russia invaded Ukraine thousands of people have been detained for protesting against the war and the recent partial mobilization mandate. The UN vote came shortly after the Russian rights group Memorial became a joint winner of the Nobel Peace Prize. Russia's UN ambassador in Geneva condemned the move as a "despicable" document, aimed at pressuring his country. In another development, Russia's President Vladimir Putin marked his 70th birthday on Friday with little fanfare, amid further signs that key parts of his invasion of Ukraine were unraveling and triggering unprecedented criticism at home. News programs made only glancing references to the birthday and public events were low key — in contrast to just a week ago when Putin held a huge concert on Red Square to proclaim the annexation of nearly a fifth of Ukrainian land. Putin was shown on state television meeting leaders of other ex-Soviet allies at an informal summit in St Petersburg on Friday, but commentators mentioned his birthday only in passing. Russian Orthodox Patriarch Kirill, a vocal supporter of the war, led birthday tributes for Putin with a prayer for God to "grant him health and longevity, and deliver him from all the resistances of visible and invisible enemies". Ramzan Kadyrov, the leader of Chechnya, a once-breakaway region Putin reconquered two decades ago, congratulated "one of the most influential and outstanding personalities of our time, the No. 1 patriot in the world". Public observation of the birthday was otherwise muted. A video circulated on pro-Russian social media channels showing a crowd of a few hundred youths in central St Petersburg waving Russian flags, and holding up red umbrellas to spell out "Putin — My President". By late afternoon such images had not appeared on Russia's major broadcasters. — Euronews