Ukraine's defense minister says the country has "extremely difficult weeks" ahead, warning of major "destruction" in an ongoing large-scale Russian offensive in the east of the country.
Russia "will try to inflict as much pain as possible," Defense Minister Oleksiy Reznikov said on April 27, warning of "destruction and painful casualties."
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His statement came as officials from about 40 officials from met for a second day at the U.S. air base at Ramstein, Germany. Reznikov met on April 27 with the ministers of several Western countries, including Germany, Poland, and Canada.
"This is a true coalition whose goal is not just to hold the Kremlin accountable, but to defeat Russian tyranny, to ensure the civilized world can win this war," he said on Facebook.
Earlier on April 27, Western countries accused Russia of "blackmail" for cutting off gas supplies to Poland and Bulgaria.
The White House said Russia's move against the two NATO allies was essentially "weaponizing energy supplies" and said Washington had expected it.
Polish Prime Minister Mateusz Morawiecki called Russia's move a "direct attack" on his country and said Poland will not purchase Russian gas from the autumn.
European Commission President Ursula von der Leyen said the Kremlin's attempt to "sow division" among EU states had failed again.
"We are prepared for this scenario," she said, adding that contingency plans have been put in place and that the EU response will be "immediate, united, and coordinated."
Gazprom said in a statement on April 27 that it had "completely suspended" gas supplies to Poland and Bulgarian for failing to pay in rubles, a condition Russian President Vladimir Putin initiated last month for "unfriendly" countries after a raft of sanctions were imposed on Russia and after the United States and other Western allies vowed to rush more and heavier weapons to Ukraine.
Poland has been a major gateway for many of the weapons already delivered, and Bulgaria has hosted Western fighter jets at a new NATO outpost on its Black Sea coast. But it still gets more than 90 percent of its gas from Russia.
Von der Leyen warned EU members against giving in to Moscow's demands for payments in rubles unless their contract is denominated in rubles. She said about 97 percent of all EU contracts explicitly stipulate payments in euros or dollars.
In a continuation of his diplomatic push, UN Secretary-General Antonio Guterres arrived in Kyiv on April 27 following talks with Putin in Moscow.
"We will continue our work to expand humanitarian support and secure the evacuation of civilians from conflict zones," he vowed. "The sooner this war ends, the better -- for the sake of Ukraine, Russia, and the world," he said on Twitter ahead of talks with Ukrainian President Volodymyr Zelenskiy.
During his talks with Putin, Guterres repeated calls for both Russia and Ukraine to work together to set up humanitarian corridors. Putin told him he hoped that negotiations could end the conflict though talks remain stalled.
On the battlefield, Russian forces pounded a steel plant in Mariupol where the city's last defenders and some civilians are holed up.
Petro Andryushchenko, an aide to the city's mayor, said there had been no let-up in air strikes on the Azovstal plant. Several recent attempts to establish a humanitarian corridor to allow civilians to escape have failed.
Russia claimed its missiles took out a "large batch" of Western-supplied weapons and ammunition being stored at an aluminum plant in the southeastern city of Zaporizhzhya.
A British intelligence report said earlier that Russian forces had targeted hangars at the plant using long-range sea-based missiles but did not specify what weapons if any were hit by the strike.
The Ukrainian Defense Ministry said on April 27 that the villages of Velyka Komyshuvakha and Zavody in the northeastern Kharkiv region and Zarichne and Novotoshkivske in the eastern Donetsk region had fallen to the Russian forces, whose aim appears to be linking territory held by Kremlin-backed separatists in the east to Russia-annexed Crimea.
The Russian Defense Ministry said on April 26 that it had gained full control of the Kherson region, which lies in the area that would provide Russia that land link.
Kherson regional Governor Hennadiy Laguta said in a video address on April 26 that the occupation meant his administration was forced to leave.
A series of recent blasts in the Russian-backed separatist region of Transdniester, which has a border with Ukraine, raised fears that the war could spill over into Moldova.
Ukrainian presidential aide Mykhaylo Podolyak on April 27 accused Moscow of wanting to use Transdniester to "destabilize" Moldova.
"If Ukraine falls, tomorrow Russian troops will be at Chisinau's gates," Podolyak said, referring to Moldova's capital, after separatist authorities in Transdniester called the blasts "terrorist attacks."
Russia on April 27 also reported several explosions and a fire on its own territory -- at an ammunition depot in the Kursk and Belgorod regions respectively, both of which border Ukraine -- the latest in a series of incidents that a top Ukrainian official called payback and "karma" for Moscow's invasion.
Podolyak, without directly admitting that Ukraine was responsible, said it was natural that Russian border areas where fuel and weapons are stored were learning about "demilitarization" -- a direct reference to the Kremlin's alleged objective for the unprovoked invasion, which it calls a special military operation to disarm and "de-Nazify" its neighbor.
"If you (Russians) decide to massively attack another country, massively kill everyone there, massively crush peaceful people with tanks, and use warehouses in your regions to enable the killings, then sooner or later the debts will have to be repaid," Podolyak said.
SEE ALSO: Russia Accuses Ukraine Of Shelling Its Bryansk Region, Kyiv Rejects ClaimThe April 27 explosions came after a major fire this week at a Russian oil-storage facility in the Bryansk region near the border.
Earlier this month, Moscow accused Ukraine of attacking a fuel depot in Belgorod with helicopters, which a top Kyiv security official denied.
The incidents have highlighted Russia's weakness in areas close to Ukraine that are vital to its military logistics chains.
In Voronezh, the administrative center of another southern region, TASS news agency cited an Emergency Situations Ministry official as saying that two explosions had been heard in the area.
Regional governor Aleksandr Gusev said that an air-defense system had detected and destroyed a small reconnaissance drone.
Kyiv has not claimed responsibility for the incidents but described them as payback. "Karma is a cruel thing," Podolyak wrote on social media.