BRUSSELS, June 20. /TASS/. The Ukrainian armed forces are facing a well-prepared Russian defense during its counteroffensive, NATO Secretary-General Jens Stoltenberg said.

"We know that Ukrainians face a difficult terrain, they face dug-in Russian resistance. The Russians have been able to establish static, well-prepared defense lines with minefields, with Dragon’s teeth, with tank trenches," he said in Flensburg, Germany, according to the NATO press service’s broadcast.

As the Russian Defense Ministry reported, Ukrainian troops have been making unsuccessful attempts at mounting an offensive since June 4, suffering losses in manpower and equipment. According to the ministry, the Ukrainian side has already lost over 7,500 servicemen during its attempts at executing the "long-promised offensive" in the South Donetsk, Zaporozhye and Donetsk areas. President Vladimir Putin also pointed out that the Ukrainian forces had not seen any success in any area.