Ukrainian President Volodymyr Zelenskyy announced the creation of an "international legion" to enlist foreign fighters. RELATED: Kharkiv invaded by Russian troops as residents hide in bomb shelters https://bit.ly/3ItRUcY The main Russian force has advanced slowly in the last 24 hours to within about 15 miles of Kyiv’s city center as they continue to face stiff Ukrainian opposition and their own logistical problems. Ukrainian forces have attacked Russian troops and combat vehicles with small arms and surface-to-air missiles, a senior Defense Department official told reporters on Monday. The official discussed the military operations on condition of anonymity. Ukrainians have also blunted the Russian advance by blowing up bridges, the official said. Since Sunday, the Russians have moved about three miles closer to the Ukrainian capital, the official said. They appear intent on encircling the city. Nearly 75% of the combat troops Russian President Vladimir Putin deployed for the war are inside Ukraine. » Subscribe to USA TODAY: http://bit.ly/1xa3XAh » Watch more on this and other topics from USA TODAY: https://bit.ly/3IyeBN6 » USA TODAY delivers current local and national news, sports, entertainment, finance, technology, and more through award-winning journalism, photos, videos and VR. #Russia #Ukraine #RussiaUkraineWar #McMaster