“This is a very big step toward the start of World War Three,” lawmaker Vladimir Dzhabarov says Poland, defending Ukraine, said missiles against Russia is “a language Putin understands” MOSCOW: Washington’s decision to let Kyiv strike deep into Russia with long-range US missiles escalates the conflict in Ukraine and could lead to World War III, senior Russian lawmakers said on Sunday. Two US officials and a source familiar with the decision revealed the significant reversal of Washington’s policy in the Ukraine-Russia conflict earlier on Sunday. “The West has decided on such a level of escalation that it could end with the Ukrainian statehood in complete ruins by morning,” Andrei Klishas, a senior member of the Federation Council, Russia’s upper chamber of parliament, said on the Telegram messaging app. Vladimir Dzhabarov, first deputy head of the Russian upper house’s international affairs committee, said that Moscow’s response will be immediate. “This is a very big step toward the start of World War Three,” the TASS state news agency quoted Dzhabarov as saying. President Vladimir Putin said in September that the West would be fighting Russia directly if it allowed Ukraine to strike Russian territory with Western-made long-range missiles, a move he said would alter the nature and scope of the conflict. Russia would be forced to take what Putin called “appropriate decisions” based on the new threats. Leonid Slutsky, chairman of the State Duma lower house’s foreign affairs committee, said that US authorization of strikes by Kyiv on Russia with US ATACMS tactical missiles would lead to the toughest response, Russian news agencies reported. “Strikes with US missiles deep into Russian regions will inevitably entail a serious escalation, which threatens to lead to much more serious consequences,” TASS news agency quoted Slutsky as saying. NATO member Poland welcomed Biden"s decision, saying missiles against Russia is “a language Putin understands.” “With the entry into the war of North Korea troops and (Sunday’s) massive attack of Russian missiles, President Biden responded in a language that (Russian President) V. Putin understands,” Foreign Minister Radoslaw Sikorski posted on X. “The victim of aggression has the right to defend himself,” Sikorski added in his post. “Strength deters, weakness provokes.” Ukrainian President Volodymyr Zelensky has long pushed for authorization from Washington to use the powerful Army Tactical Missile System, known by its initials ATACMS, to hit targets inside Russia. Russian President Vladimir Putin has warned that approval would mean that NATO was “at war” with his country — a threat he has made previously when Ukraine’s Western backers have escalated their military assistance to Kyiv.