Advisor to the head of the Ukrainian president's office said the frontlines between Russian and Ukrainian troops are "practically frozen" as Russia does not have enough combat strength to advance further.
Neither the Russian nor the Ukrainian side currently has the strength to make significant progress, although tactical attacks were still being carried out, Oleksiy Arestovych said in a post on Facebook on Sunday.
The Ukrainian general staff fear that Belarus might actively join the war and claimed evidence of Belarusian troops being prepared for a direct invasion.
While Russian troops did invade Ukraine from Belarusian territory, the authoritarian president of Belarus, Alexander Lukashenko, has so far rejected an active involvement of his own troops in the war.
“(Over the past day) there were practically no rocket strikes on (Ukrainian) cities,” Arestovych added.
Russian soldiers and officers are feeling the pressure as commanders are being accused of "cowardice and weakness of character" after inspections by Russia's Federal Security Service, Arestovych claimed.
Earlier on Sunday, the Ukrainian military said it had inflicted more losses on Russian forces in ongoing clashes, with approximately 14,700 Russian soldiers killed in Ukraine so far.
Ukrainian forces have destroyed a total of 96 Russian aircraft, 118 helicopters, 476 tanks, 1,487 armored carriers, 947 vehicles, 21 unmanned aerial vehicles (UAVs), 60 fuel tankers and three boats, according to the latest update from the Ukrainian General Staff.
At least 230 Russian artillery systems, 74 multiple rocket launcher systems and 44 air defense systems have also been destroyed, it added.
Claims on casualties and damages from both sides, however, have not been independently verified.
According to U.N. estimates, at least 902 civilians have been killed and around 1,460 injured in Ukraine since Russia launched a war on its western neighbor on Feb. 24.
The U.N. has said the real figures are likely to be much higher as conditions on the ground make verification difficult.
The hostilities have also driven 10 million people from their homes, according to the U.N. refugee agency.
U.N. data shows almost 3.4 million refugees have fled from Ukraine since the war began, with more than 2 million taken in by neighboring Poland, close to 530,000 by Romania and over 362,000 by Moldova.
Some 6.5 million people are estimated to be internally displaced in the country.
