Russia's drone attacks on Ukraine's infrastructure have begun to target military recruitment centers, according to a data analyst group. Armed Conflict Location and Event Data (ACLED) said Russia began to hit enlistment centers in recent weeks in a concerted effort to disrupt Ukraine's mobilization.

Russia launched four missiles and 136 drones into Ukraine overnight into Monday morning, according to Ukraine's air force.

Ukraine says it will give defense firms a detailed report of how their weapons tech fares in combat against Russia's troops.

Russia hit Ukraine with the largest drone and missile assault in history, surpassing its previous record by nearly 750 drones and missiles.

President Donald Trump, who has recently sharpened his tone against Russia, threatened harsher sanctions earlier this month if a peace deal was not reached within 50 days.

"President Putin has repeatedly spoken of his desire to bring the Ukrainian settlement to a peaceful conclusion as soon as possible. This is a long process, it requires effort, and it is not easy," Mr Peskov said.