President Volodymyr Zelenskiy warned on Tuesday against expecting too much success too quickly in Ukraine's campaign to reclaim occupied lands as the military said Russian forces were gearing up for fresh attacks in different sections of the front.
There has been little movement along the 1,000-km (600-mile) front line in recent months. A Ukrainian counteroffensive launched in June has achieved only limited success despite capturing several villages in the east and south.
Zelenskiy has previously rejected criticism, mainly from Western sources, that the counteroffensive was proceeding too slowly, saying the war was not akin to a Hollywood movie set.
And while applauding Ukrainian offensive moves that have restricted the operations of Russia's Black Sea Fleet, he said no one should expect rapid success stories in repelling Russia's 20-month-old invasion.
"The modern world is set up in such a way that it becomes accustomed to success too quickly. When the full-scale aggression began, many in the world did not think Ukraine would endure," Zelenskiy said in his nightly video address.
"The colossal things done by our people, by our soldiers are now taken for granted ... No matter what, we have to do our part, defend our state, Ukrainian independence."
Zelenskiy said a meeting with senior commanders had considered sectors engulfed by the fiercest fighting in the east and northeast, including the key areas of Avdiivka and Kupiansk where Russia has been on the offensive in recent weeks.
Vitaliy Barabash, head of the military administration in Avdiivka, said the shattered eastern city was bracing for a new wave of the attacks it had been withstanding since mid-October.
"The enemy is bringing in forces and equipment. Our boys are preparing for a new wave," Barabash told national television.
"There are 40 to 50 shelling incidents per day hitting the city and hundreds hitting our positions. And they will keep attacking, paying no heed to their losses."
Avdiivka, with its vast coking plant, was briefly captured in 2014 when Russian-backed separatists seized chunks of land in the east, but Ukrainian forces have since put up fortifications.
Volodymyr Fityo, a spokesperson for Ukraine's ground forces, said Russian forces were also focused on Kupiansk - a city in the northeast overrun by Russia in the early days of the invasion, but recaptured by Ukrainian forces last year.
"Our defence forces continue to repel enemy attacks in the Kupiansk sector," Fityo told a briefing, outlining eight Russian air strikes on the village of Synkivka, northeast of the town.
Russian accounts of the fighting said Moscow's forces had conducted successful attacks near the town of Bakhmut - a largely destroyed town captured by Russian forces in May.
Reuters could not verify accounts of fighting from either side.
