Russian President Vladimir Putin said he signed a decree on partial mobilization beginning Wednesday.
Putin said in a televised address on Wednesday that his aim was to "liberate" Ukraine's Donbas region and that he was defending Russian territories, claiming that people in the region did not want to return to what he called the "yoke" of Ukraine.
The Russian leader said he was "talking about partial mobilization, that is, only citizens who are currently in the reserve will be subject to conscription, and above all, those who served in the armed forces have a certain military specialty and relevant experience."
Russian Defense Minister Sergei Shoigu said 300,000 reservists would be called up.
Putin also again appeared to make a veiled reference to the potential use of nuclear weapons should the situation escalate.
"When the territorial integrity of our country is threatened, we will certainly use all the means at our disposal to protect Russia and our people. This is not a bluff," Putin said.
The West was aiming to "weaken, divide and ultimately destroy our country," Putin said.
Putin's address came a day after Russian-controlled regions in eastern and southern Ukraine announced so-called "referendums" on joining Russia.
The "referendums," to be held between September 23 and 27 in Luhansk, Donetsk, Kherson and Zaporizhzhia provinces, represent around 15% of Ukrainian territory, or an area about the size of Hungary.
Putin's move an 'act of desperation,' says Germany's Scholz
German Chancellor Olaf Scholz called Putin's partial troop mobilization plan an "act of desperation" that will make "everything much worse."
"Russia cannot win this criminal war," Scholz said on the sidelines of the UN General Assembly in New York.
Scholz said that Putin had "completely underestimated" the situation in Ukraine from the beginning, referring to "the resistance and the will of the Ukrainians to resist" and "the unity and determination" of Ukraine's friends.
German Finance Minister Christian Lindner told DW that Ukraine and its supporters such as Germany will not be intimidated by Putin.
"For me, this is a sign of weakness. We have to be prepared for a long conflict with Russia. That's why we need to discuss among allies and partners how we can support Ukraine in an even longer struggle for peace and freedom," Lindner said in an interview.
Meanwhile, German Vice Chancellor Robert Habeck said Germany was deciding its response to Putin's call for partial mobilization.
Putin's speech was "another bad and wrong step from Russia, which of course we will discuss and consult on politically regarding how to respond," Habeck said.
Putin's nuclear gamble is 'unacceptable,' says EU spokesman
Peter Stano, the spokesman for the European Commission, accused the Russian president of a "very dangerous nuclear gamble," alluding to Putin's threat of "using all means," to protect Russia.
Stano added that it was important for the international community to put more pressure on Putin's "reckless behavior."
"Putin is doing a nuclear gamble. He's using the nuclear element as part of his arsenal of terror. It's unacceptable," Stano said.
Stano made the comments at a press briefing, and added that EU member states had already held a "coordination meeting where discussions have been held in terms of an EU response to the continuation of the war of aggression against Ukraine."
Similarly, European Council President Charles Michel separately added Wednesday that there was only "one aggressor, Russia, and one aggressed country, Ukraine."
He said that EU's support for Ukraine remained "steadfast."
Troop mobilization likely 'costly for Putin' domestically, says expert
Domitilla Sagramoso, a security and Russia expert at King's College London, told DW that Ukrainian gains near Kharkiv "forced" Putin to make a decision to either "cut his losses and go, which he is not ready to do, or escalate and call for partial mobilization, which is also very costly for him internally."
She added Putin is "under a lot of pressure from those in the military" to change tactics.
"I think Russia faces a lot of challenges with this mobilization. It's going to be very costly. It doesn't have the right infrastructure to actually train and equip all these forces," Sagramoso added.
Opposition calls for protests against Putin's plans
Russian opposition leader Alexei Navalny said it was "clear that the criminal war is getting worse, deepening, and Putin is trying to involve as many people as possible in this."
Navalny is currently in jail and recorded a video message which was published by his lawyers.
Other groups against war, like the Youth Democratic Movement of Russia (Vesna), called on Russians to protest against Putin's mobilization plans.
"This means that thousands of Russian men — our fathers, brothers and husbands — will be thrown into the meat grinder of war," the Vesna coalition said.
Lithuania raises army readiness, Finland monitoring situation
Lithuanian Defense Minister Arvydas Anusauskas said Lithuania was raising the readiness level of its army's rapid response force "to prevent any provocations from the Russian side" following news of Russia's partial mobilization of troops.
"Since Russia's military mobilization will also be carried out in the Kaliningrad region, in our neighborhood, Lithuania cannot just watch," Anusauskas wrote on Facebook.
Kaliningrad is a Russian exclave and lies between Lithuania and Poland, countries that are both members of NATO and the European Union.
Finland's Defense Minister Antti Kaikkonen said the military situation was stable and calm. Finland shares a land border with Russia.
"Our defense forces are well prepared and the situation is closely monitored," Kaikkonen said.
Putin speech was 'predictable,' says Ukrainian presidential adviser
Mykhailo Podolyak, an adviser to Ukraine's President Volodymyr Zelenskyy, told Reuters news agency that Putin's speech was an "absolutely predictable appeal, which looks more like an attempt to justify their own failure."
"The war is clearly not going according to Russia's scenario and therefore required Putin to make extremely unpopular decisions to mobilize and severely restrict the rights of people," Podolyak said.
Zelenskyy himself, who will speak to the UN General Assembly via pre-recorded video address on Wednesday, later told Germany's Bild TV that he did not believe Putin's threats about the potential use of nuclear weapons.
With regards to mobilizing reservists, Zelenskyy said Russia had already deployed "cadets" in Ukraine who "could not fight" and had fallen. He said Russia's president "wants to drown Ukraine in blood, but also in the blood of his own soldiers."
UK, US also denounce Putin
The UK's Defense Minister Ben Wallace said on Wednesday that mobilization of Russian troops amounted to an admission of defeat by the Russian president.
Putin's "invasion is failing" and "[Putin] and his defense minister have sent tens of thousands of their own citizens to their deaths, ill equipped and badly led," Wallace said in a statement.
Gillian Keegan, a minister at the British Foreign Office, told Sky News that Putin's speech was a worrying escalation and that the threats he made should be taken seriously.
"The overall address clearly was more of Putin's lies, it was a rewriting of history," Keegan told the TV channel.
US Ambassador to Ukraine Bridget Brink tweeted that "sham referenda and mobilization are signs of weakness, of Russian failure"
She added the US would never recognize Russia's claim "to purportedly annexed Ukrainian territory" and the US continues to "stand with Ukraine for as long as it takes."
msh, jsi,dvv,rm/wd (AFP, AP, Reuters)