North Korean soldiers have suffered several hundred casualties while fighting against Ukrainian forces in Russia's Kursk region, according to a US military official. The number of casualties far exceeds previous figures provided by US officials. White House spokesperson John Kirby described the North Korean troops' offensive as 'massed, dismounted assaults' and criticized Russian and North Korean military leaders for treating the troops as expendable. President Joe Biden is expected to approve another security assistance package for Ukraine in the coming days.