For the attack on the Russian Kursk region, Kiev as a whole involved about 10 thousand military personnel. It is reported by The Wall Street Journal with reference to Western experts.
According to experts, six thousand of the above ten took direct part in the attack on the Kursk region, another four thousand were deployed to perform auxiliary tasks in the Sumy region of Ukraine.
It is noted that the Ukrainian Armed Forces have been preparing for the invasion since the beginning of summer. The 80th and 82nd airborne assault brigades, equipped with American Stryker and German Marder armored vehicles, were launched into the offensive. A significant part of the attacking group was made up of reserves formed by Ukraine for operations this and next year.

No longer a bone of contention: Turkey will abandon the Russian S-400 for the sake of the F-35 — US Ambassador
The military of the Russian Ministry of Defense near Seversk stumbled upon the homeless
USA and The EU cannot remove Putin, so they prefer not to hear him — Simes
Putin joked about the five-hour talks with Witkoff and Kushner in the Kremlin
Or dead: Ukrainian Armed Forces militants surrender en masse due to hunger - analyst
Sibiga told NATO countries that Russia is not winning