(CN) — With the United States saying Russia needs to suffer a crippling defeat, the rhetoric coming from Moscow is getting more heated too with a warning from its foreign minister that the Ukraine conflict could spiral out of control into a new world war. 

The escalating war of words between Moscow and Washington comes at a moment when the battlefield is expanding with more explosions being reported on Russian territory and now also in Transnistria, a pro-Russian breakaway region inside the tiny country of Moldova, which is sandwiched between Romania and Ukraine. 

Meanwhile, Western allies met in Germany on Tuesday to make new pledges of military support to Ukraine. In a significant shift for war-wary German Chancellor Olaf Scholz, Germany said on Tuesday it was sending anti-aircraft systems to Kyiv. Scholz and his Social Democrats – who until the outbreak of war viewed close ties to Russia as beneficial – are under immense pressure from coalition partners to do more to hurt Russia. The European Union also is moving toward partially blocking Russian oil and natural gas, which would be another major shift. 

On Tuesday, United Nations Secretary-General Antonio Guterres was in Moscow to urge Russian President Vladimir Putin to end the war in Ukraine and help civilians trapped in the war zone get to safety, especially those inside a besieged steelworks’ bunker in Mariupol where Ukrainian forces are surrounded by Russian troops. At a news conference, Guterres said the war risked causing famine in many parts of the world. Guterres was headed to Kyiv next, but there was little hope his trip would yield breakthroughs.    

Inside Ukraine, fighting raged on Tuesday with reports that Russian forces were trying to break through Ukrainian defensive lines in Donbas, eastern regions of Ukraine that Russia is seeking to seize. The battle over Donbas is seen as a decisive phase of the war because a good part of Ukraine’s army is located here, though Ukrainian forces are reportedly outnumbered.  

Independent information from the front lines has been scant, but images from Ukrainian and Russian sources show numerous dead bodies, intense fighting, destroyed equipment, rockets streaking through the sky and soldiers sheltering in extensive trench systems.  

The ominous language issued from the Kremlin about a potential World War III came after U.S. Secretary of State Antony Blinken and U.S. Defense Secretary Lloyd Austin visited Ukrainian President Volodymyr Zelenskyy in Kyiv on Sunday with promises for more weapons to help Ukraine defeat Russia and make it so weak as to be unable to carry out future invasions. 

“We want to see Russia weakened to the degree that it can’t do the kinds of things that it has done in invading Ukraine,” Austin said, a comment that made headlines in Europe by late Monday. His remarks fueled Russian allegations the West is seeking to overthrow Putin and destroy Russia as a state. 

Austin said Russia “has already lost a lot of military capability” and that “we want to see them not have the capability to very quickly reproduce that capability.” 

Speaking on Russian state television on Monday night, Russian Foreign Minister Sergey Lavrov warned about the danger of a third world war, according to Interfax, a Russian state news agency. 

“The danger is serious, it is real, it cannot be underestimated,” Lavrov said on Channel One. He compared the tensions between the West and Russia to the 1962 Cuban missile crisis that brought the world to the brink of nuclear war. 

He warned about a lack of clear rules governing the behavior of superpowers because of the dismantling of arms control and nuclear non-proliferation treaties since the end of the Cold War and that a trusted “channel of communication” does not exist today as it did between Soviet and American leaders in 1962.