KYIV, June 30 (Reuters) - Russian forces abandoned the strategic Black Sea outpost of Snake Island on Thursday in a victory for Ukraine that could loosen the grip of Russia's blockade on Ukrainian ports.
Russia said it had decided to withdraw from the outcrop off Ukraine's southwestern coast as a "gesture of goodwill" to show Moscow was not obstructing U.N. attempts to open a humanitarian corridor allowing grains to be shipped from Ukraine.
Ukraine said it had driven the Russian forces out after an artillery and missile assault overnight.
"KABOOM!" tweeted Andriy Yermak, Ukrainian President Volodymyr Zelenskiy's chief of staff. "No Russian troops on the Snake Island anymore. Our Armed Forces did a great job."
In contrast, however, a Ukrainian official in the heavily fought eastern province of Luhansk described difficulties for Ukrainian forces in the city of Lysychansk on Thursday.
Russian artillery shelled from different directions while the Russian army was approaching from different sides, regional governor Serhiy Gaidai said on Ukrainian television.
"Residents have been told to remain in underground shelters indefinitely as it is very dangerous," Gaidai said.
An official from the pro-Russian separatist administration in Luhansk province told RIA news agency the Lysychansk oil refinery was now fully controlled by Russian and pro-Russian forces, and all roads to Lysychansk were also under their control. Ukraine says the main road out is largely impassable because of fighting, but the city is not yet fully cut off.
In his nightly video address, Ukrainian President Volodymyr Zelenskiy commented on both Snake Island and the Donbas region, which comprises Donetsk and Luhansk provinces on the border with Russia.
The recovery of Snake Island was significant for the Black Sea situation but "it does not yet guarantee security. It does not yet ensure that the enemy will not come back," he said.
In Luhansk and Donetsk, the Russians "have simply brought in all their reserves to hit us," Zelenskiy said.
RUSSIAN FIREPOWER
Russian forces have been trying to encircle Lysychansk since they captured Sievierodonetsk, on the opposite side of the Siverskyi Donets River, last week after weeks of heavy fighting.
Russia has focused its firepower on capturing cities and towns in the Donbas region.
Despite yielding ground and taking punishing losses in the Donbas in recent weeks, Ukraine hopes to inflict enough damage to exhaust Russia's advancing army. Ukrainian forces have been mounting a counter-attack in the south of the region.
Gaidai and Zelenskiy both mentioned Russia's overwhelming advantage in equipment and artillery in the battle for Lysychansk. Ukraine's Western allies have been sending weapons and the Kyiv government was given another boost with the United States saying it would provide a further $800 million in weapons and military aid.