Ukraine and Russia: What you need to know right now

May 30 (Reuters) - Russian forces intensified their attacks with barrages of heavy artillery to capture a key Ukrainian city in the southeastern region of Donbas, whose full takeover Moscow's top diplomat said was now an "unconditional priority". read more

* Ukrainian President Zelenskiy visited troops in the northeastern Kharkiv region, his office said, Zelenskiy's first official appearance outside Kyiv region since the Russian invasion began on Feb. 24. read more

* Several explosions were heard in Kharkiv city hours after Zelenskiy's visit, a Reuters journalist said.

* Russian foreign minister Lavrov is quoted as saying the "liberation" of Ukraine's eastern Donbas region is an "unconditional priority" for Moscow; other territories should decide their future for themselves. read more

* Russian shelling has destroyed all of the critical infrastructure in Sievierodonetsk city, Zelenskiy said, describing the taking of the city as Russia's "principal aim" right now. read more

* The Russian defence ministry said Russian missiles have destroyed a large arsenal of the Ukrainian army in the city of Kryvyi Rih in central Ukraine, state news agency TASS quoted the ministry as saying.

* Russia said it used missile strikes to destroy Ukrainian command posts in Bakhmut and Soledar. Both towns are on an important road running southwest from Lysychansk and Sievierodonetsk.

* Reuters could not independently verify the battleground accounts.

* European Union leaders will meet on Monday to declare continued support for Ukraine to help it fend off Russia's assault, but the talks will be overshadowed by their failure to agree on a new sanctions package against Moscow. read more

* Turkish President Tayyip Erdogan said talks last week with Finnish and Swedish delegations were not at the "expected level" and Ankara cannot say yes to "terrorism-supporting" countries entering NATO, state broadcaster TRT Haber reported. Turkey has objected to Sweden and Finland joining the alliance and Erdogan appears to be holding to his position. read more

* Zelenskiy said in a television interview he believed Russia would agree to talks if Ukraine could recapture all the territory it has lost since the invasion. But he ruled out the idea of using force to win back all the land Ukraine has lost to Russia since 2014.

* Germany has agreed to change its constitution to allow for a credit-based special defense fund of 100 billion euros ($107.35 billion) proposed after Russia's invasion of Ukraine, the German finance ministry announced on Sunday. The money is to be used over several years to increase Germany's regular defense budget of around 50 billion euros, enabling the country to meet a NATO target of spending 2% of economic output on defense annually. read more

* Canada has asked South Korea to supply it with artillery rounds, Seoul said on Monday, apparently to "backfill" supplies that Ottawa has sent to Ukraine, upping pressure on South Korea to provide - at least indirectly - lethal aid in the war. read more