NATO said Wednesday that its latest estimates bring the total number of Russian soldiers killed in the war in Ukraine over the past four weeks at between 7,000 to 15,000. Since it sent troops into the country, Russia has been facing fierce resistance from Ukraine defenders, denying Russian President Vladimir Putin his expected swift victory.

NATO said it based its rough estimate on data it received from both Russian and Ukrainian officials as well as intelligence from other sources. Ukraine has not officially released its casualty figures, but President Volodymyr Zelenskiy stated two weeks ago that more than 1,300 of his troops had been killed in the war.

Russia has also not released any official figures, but it did claim that only about 500 of its soldiers have been killed. Russia has denied claims that it had lost thousands of soldiers during the first few weeks of the war. A NATO official who declined to be named estimated that Russia may have lost more troops than initially expected.

When Russia launched its invasion on February 24, in what was the largest attack on a European country since World War II, a quick overthrow of Ukraine's government appeared imminent. However, Russia did not expect the Ukrainian military to put up such a fight. After four weeks of fighting, Russian forces remained bogged down in some areas after facing intensifying resistance.

With its ground forces being halted or stopped by hit-and-run Ukrainian battalions armed with Western-supplied weaponry, Putin's forces are blasting targets from afar, reverting to the methods that it used to reduce towns to ruins in Syria and Chechnya. Intelligence reports indicate that Russian troops appear to be setting up defensive positions around the capital of Kyiv, as progress in forcefully taking control of the city has slowed down.

Ukrainian military officials have claimed to have killed six Russian generals so far, the most ever killed in such a short time during a war. Russia denied the claims and acknowledged only the death of one general.

Zelenskyy, who has captivated the world with impromptu videos and speeches to legislatures pleading for military aid for his country, has called for people all over the world to show support for Ukraine, saying the conflict affects every free person on the planet.

Secretary of State Antony Blinken publicly claimed that Russian forces are guilty of committing war crimes in Ukraine. He added that the U.S. would endeavor to prosecute those guilty of such crimes. Blinken said he had received evidence of indiscriminate or intentional assaults on civilians, as well as the indiscriminate devastation of residential complexes, schools, hospitals, shopping malls, and other locations.

Despite this, fundamental Russian objectives remain unmet. Kyiv has been shelled several times but still remains under Ukrainian control. On Wednesday, the city was rattled by near-constant shelling and shooting, with air-raid sirens blaring and plumes of black smoke rising from the city's western fringes, in areas where the two sides are still fighting for control.