By Maria Starkova and Ronald Popeski
LVIV (Reuters) -Ukraine's attacks on the Russian Navy in the Black Sea have crippled Moscow's war efforts, President Volodymyr Zelenskiy said on Tuesday, seeking to rally his troops even as the outside world expects instant successes.
Despite Kyiv's gruelling months-long offensive, the vast frontline in Ukraine's east and south has moved little in the past year, spurring criticism and impatience among some of Ukraine's Western allies.
"We live in a world that gets used to success too quickly. When the full-scale invasion began, many people around the world did not believe that Ukraine would survive," Zelenskiy said in his nightly video address. "Glory to all those who do not retreat, who do not burn out, who believe in Ukraine just as they did on February 24, and who has been fighting for unwaveringly."
The war, which Russia launched on Feb. 24, 2022, is now in its 20th month and has no end in sight. Russian forces have geared up for fresh attacks in different sections of the front and are suffering heavy losses.
Zelenskiy said his troops have succeeded in diminishing Moscow's military strength in the Black Sea, which he said with greater support from Kyiv's allies could lead to Ukraine's ultimate victory over Russia.
The Black Sea has become a crucial theatre in the war. Ukraine's increased air and sea drone attacks on Russian military targets there have damaged ship and naval repair yards in the port of Sevastopol, and struck other targets.
Moscow uses its fleet in the Black Sea to launch long-range strikes on Ukraine. But for President Vladimir Putin, the waters - which connect to the Mediterranean Sea - are also an important springboard for projecting power into the Middle East, Europe and the West.
"When we ensure even more security to the Black Sea, Russia will lose any ability to dominate in this area and expand its malign influence to other countries," Zelenskiy said.
The full extent of the damage that Ukraine has done in recent months to the Russian Black Sea Fleet remains unclear. The Russian defence ministry's laconic statements mostly claim success in destroying the weapons, with little evidence.
"Ukraine's success in the battle for the Black Sea will go down in history books, although it's not being discussed much today," Zelenskiy said.
STRUGGLE AT THE FRONTLINE
At the frontline, however, there has been a struggle.
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.
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.
Ukraine's ground forces said on Tuesday that 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.
Russia' Tuesday 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.
(Reporting by Ron Popeski and Maria Starkova; Writing by Ron Popeski and Lidia Kelly; Editing by Stephen Coates and Gerry Doyle)