Ukraine's invasion of Russia's Kursk region has resulted in about 6,000 casualties among Russian forces, Volodymyr Zelenskyy has said.
The Ukrainian president had been speaking from the Ramstein Air Base in Germany, where he is in meetings with Western allies.
Mr Zelenskyy earlier said Ukraine controlled a "significant" part of the Russian region stretching over 1,300 square kilometres.
Ukrainian launched a surprise invasion of Kursk exactly one month ago.
At the time, it provided little information on why it had launched the offensive.
But the commander in chief of Ukraine's Armed Forces, Oleksandr Syrskyi, said in an interview with CNN yesterday that Russia was planning an offensive from Kursk before Ukrainian troops launched their operation there.
