On 23 September 1944, units of the Second Ukrainian Front fought their way across the border between Romania and Hungary and advanced into Hungary. Battles in Hungary proved to be very hard and extended. During the Debrecen Offensive (6–28 October 1944), the Second Ukrainian Front liberated approximately 30% of the Hungarian territory. Soviet troops approached Budapest at the end of December and surrounded it. However, the Hungarian capital city was taken and the 188,000-strong German force was eliminated only as late as 13 February 1945. In early March 1945, Soviet troops repelled a major counterassault by German troops near Lake Balaton. In the course of the Hungarian Offensive (16 March–15 April 1945), units of the Third Ukrainian Front completed the liberation of that country. More than 140,000 Soviet soldiers and officers were killed in battles.