KYIV -- There is growing evidence that Ukraine is managing to inflict significant casualties on Russian forces as they try to advance deeper into the country -- and that the swift strike Russia hoped to carry out on the capital, Kyiv, has been slowed by intense and popular resistance.
Russia hasn't managed to make significant progress in the last two days. The main Russian force pushing down from Belarus towards Kyiv does not appear to have advanced closer towards the city since coming within about 20 miles, although smaller advanced groups have been fighting gun battles with Ukrainian forces inside the capital since at least Friday.
Ukraine's military claims the Russian troops are struggling with fuel and logistics supplies. Images and videos of destroyed Russian military vehicles and tanks, which have been verified, have been circulating online.
One example of the effective Ukrainian resistance took place Sunday when Russia appeared to mount a half-hearted attempt to destroy resistance in Ukraine's second city, Kharkiv.
Russian special forces units in light armored vehicles tried to push into Kharkiv after indiscriminately bombarding the city with artillery, but they were rapidly destroyed by Ukrainian troops and volunteer territorial defense, according to videos posted online.
Kharkiv's Mayor Oleg Sinegubov on Sunday night pushed a triumphant message, saying that "control over Kharkiv is completely ours" and that Ukrainian forces had succeeded "in a full clearing of the city of the enemy."
Sinegubov said dozens of Russian troops had surrendered with little fight, sometimes in whole groups of five to 10 men, with some abandoning their equipment.
A number of military analysts -- including those that correctly predicted the invasion -- believed Russia had hoped for a lightning "shock and awe" advance to the edge of Kyiv in the first days that would lead to President Volodymyr Zelenskyy's government surrendering without Russia needing to actually seize the city. Instead, the resistance is growing, officials said.
"It is clear they hoped to get Zelenskyy to surrender quickly without inflicting heavy casualties on the Ukrainian military [and] civilians. That failed, but their execution still appears to be fairly restrained," Rob Lee, analyst from Kings College London's War Department, wrote on Twitter on Sunday.
Lee said that strategy had now failed, and that Russia would have to move to a plan B, which he feared would mean "more force."
Time is working against Russia. Ukrainian popular resistance is gaining in self-confidence, and the Russian piecemeal strategy so far has allowed cities more time to set up defenses, putting in place barricades and distributing thousands of weapons.
In Berdyansk, the only major city Russia has gained full control of, videos posted to social media Monday showed a crowd of residents angrily chanting a slogan insulting President Vladimir Putin at Russian troops guarding a government building on the main square.
At the same time, the international response is also growing, with more sanctions and moves aimed at crippling Russia's economy, while European countries are sending more and more weapons to bolster the Ukrainian defense, with the European Union also announcing that for the first time it would provide Ukrainian officials with military support.
Russia has so far held back its main army and has been using its air and artillery power against military targets, avoiding widespread, intense bombardment against civilian areas. Analysts, including Lee, said Russia appeared to have initially sought to inflict limited casualties on Ukrainian civilians and the military, likely out of concern about backlash in Russia and making it harder to achieve a swift political change in Ukraine, as well as a stronger international reaction.
U.S. officials and independent analyst now fear if Russia's attempt to overpower Ukraine quickly fails, it may turn to using more brute force to achieve it. That could mean unleashing indiscriminate artillery and airstrikes to destroy Ukraine's military and terrorize civilians, as well as besieging cities.
That already appears to be happening in Kharkiv, where Russia in the last two days has fired heavy artillery, including "Grad" multiple rocket launchers onto the city, causing significant damage to civilian buildings.
"I think today we've seen a shift in Russian targeting towards critical civilian infrastructure, greater use of MLRS, and artillery in suburban areas. Unfortunately, my concern that this was going to get a lot more ugly and affect civilians is starting to materialize," Michael Kofman, an analyst at CNA, who also predicted the invasion as likely, tweeted late Saturday.
U.S. officials caution, though, that Russia still has major combat power yet to be deployed, with roughly half its forces massed near Ukraine still not engaged. A massive 3-mile-long column of hundreds of vehicles has formed up in northern Ukraine after crossing from Belarus and appears to be moving towards Kyiv.