Moscow/New York, 22 September 2022 (dpa/MIA) - EU foreign policy chief Josep Borrell has promised new sanctions targeting Russia following President Vladimir Putin's latest escalation in his war against Ukraine. "We decided to bring forward as soon as possible additional restrictive measures against Russia in coordination with partners," Borrell said late on Wednesday following a meeting of EU foreign ministers on the sidelines of the UN General Assembly in New York. The meeting was convened by Borrell after Putin ordered the partial mobilization of reservists in order to bolster his military's flagging efforts in Ukraine. "On 21 September, Russia chose a path of confrontation by announcing a partial mobilisation in Russia, by supporting the organisation of illegal 'referenda' in the Ukrainian territories currently occupied by Russia and by threatening again with the use of weapons of mass destruction," Borrell said in a statement. "The references to nuclear weapons do not shake our determination, resolve and unity to stand by Ukraine and our comprehensive support to Ukraine's ability to defend its territorial integrity and sovereignty as long as it takes," he added. Earlier in the day, Putin signed a decree to partially mobilize the reservists in the country's armed forces, sparking protests in several Russian cities. As Putin looks for ways to throw more resources at his troubled invasion of Ukraine, he warned other states not to attack Russian territory, and alluded to nuclear retribution if someone chose to do so. "If the territorial integrity of our country is threatened, we will absolutely use all available means to protect Russia and our people. This is not a bluff," he said in a televised address. Hundreds of Russian demonstrators were detained at rallies against the mobilization measure. Civil rights group OVD-Info counted 1,350 arrests by Wednesday evening across 38 cities across the vast country, where anti-government rallies are routinely repressed. It said 500 demonstrators were held in Moscow and 556 in St Petersburg. Putin announced the mobilization as he said that he would support planned referendums in the occupied regions of Luhansk, Donetsk, Kherson and Zaporizhzhya later this week, in which people will be asked to join Russia. The vote has been panned as a "sham" by the West, as it is being conducted during a military occupation and without outside oversight. However, if Putin were to be able to report that these areas had voted to become Russian, any attack by Ukraine to free them would fall under his threat of doing anything to protect his country's "territorial integrity." Russian Defence Minister Sergei Shoigu said some 300,000 reservists of 25 million available will be called up. Shoigu also put the losses suffered by Russia's army during its invasion of Ukraine at 5,937 personnel. It is the first time in months that Russia has officially published figures. Independent observers, however, believe Russia's losses are significantly higher. The call to mobilization prompted criticism from Ukraine and further abroad, with many saying it's a sign that Putin's gambit is failing. "All this can only be explained against the background of the fact that the Russian attack on Ukraine has not been successful," a government spokesperson quoted German Chancellor Olaf Scholz as saying in Berlin on Wednesday. US Secretary of State Antony Blinken said Putin's latest move "reflects the Kremlin's struggles on the battlefield, the unpopularity of the war, and Russians' unwillingness to fight in it." "President Putin is not operating from a position of strength," Blinken said in a statement. "Rather, this is another sign of his failing mission." European Commission President Ursula von der Leyen echoed Blinken's comments, telling CNN Putin was "showing his weakness." Von der Leyen also said that Putin "will have to pay massive costs" for the invasion, adding that "we will never bow to blackmail" over Putin's nuclear threat. Ukrainian President Volodymyr Zelensky told the UN General Assembly the move showed Russia is not interested in peace. "They talk about the talks but announce a military mobilization. They talk about the talks but announce pseudo referendums in the occupied territories of Ukraine," Zelensky said. "Russia wants war." US President Joe Biden told the assembly that the war "is about extinguishing Ukraine's right to exist as a state, plain and simple. And Ukraine's right to exist as a people." Meanwhile, Kiev announced that 215 people, including fighters captured at the Azovstal steelworks in Ukraine, were exchanged for pro-Russian politician Viktor Medvedchuk and Russian soldiers in a major prisoner swap.