In its latest quarrel over Western sanctions placed on the country for the war in Ukraine, Russia warned Lithuania on Tuesday that it will face a "serious negative impact" for restricting some rail shipments to Moscow's Baltic Sea enclave of Kaliningrad.

Russian soldiers and separatists in eastern Ukraine made additional advances, moving towards Lysychansk, the main bastion of the Ukrainian military in an area that Moscow claims for the rebels and is part of the Donbas region.

Ukraine continues to request that the West deploy additional artillery. Tuesday, Defense Minister Oleksandr Reznikov confirmed the arrival of German self-propelled howitzers.

In retaliation for Western sanctions, Russia has begun pumping less gas through Ukraine to Europe. European Union states from the Baltic Sea in the north to the Adriatic Sea in the south have proposed steps to deal with a supply crisis following Russia's invasion of Ukraine at the end of February, which placed energy at the center of an economic conflict between Moscow and the West.

Robert Habeck, the German minister of economy, stated that the decreased flows constitute an economic onslaught against Germany that "cannot be allowed to succeed."

The diplomatic focus has shifted to Kaliningrad, a roughly one-million-person Russian city between Poland and Lithuania. It is connected to the rest of Russia by train through Lithuania, a member of the European Union and NATO.

Lithuania has closed the route for transporting steel and other ferrous metals, citing EU restrictions that went into effect on Saturday. Lithuania is also obstructing the transit of food, compromising the region's food security, according to a foreign ministry spokesperson quoted by the TASS news agency.

Lithuanians residing on the opposite side of the border expressed confidence in NATO as a deterrence against future Russian attacks.

"Nothing bad will happen ... because Lithuania is in NATO and the European Union," said Vitalijus Sidiskis, a 59-year-old insurance worker, admitting that it was difficult to anticipate what Russia may do.

In the meantime, Estonia summoned the Russian ambassador on Tuesday to protest the June 18 violation of Estonia's airspace by a Russian helicopter.

There was no quick response from Russia.

'Consequences'

The secretary of Russia's Security Council, Nikolai Patrushev, traveled to Kaliningrad to preside over a security meeting. He added that Lithuania's acts demonstrated that Russia could not trust the West, which had violated written agreements about Kaliningrad.

In response, "Appropriate measures" are being formulated, Patrushev was cited as saying by the state-run news agency RIA, adding that "their consequences will have a serious negative impact on the population of Lithuania."

Tuesday, Moscow called EU representative Markus Ederer to the Russian Foreign Ministry. Peter Stano, a spokesman for the EU, stated that at the meeting, Ederer asked the Russians to stop escalators' actions and language.

The standoff provides a new source of conflict in the Baltic. This area was already slated for a security makeover that would limit Russia's naval might as Sweden and Finland seek to join NATO and bring practically the whole coast within alliance territory.

The EU attempted to shift blame away from Lithuania by claiming the policy was joint action by the group.

According to EU diplomats, Ukraine will become an official candidate for European Union membership on Thursday in a symbolic move.

On Tuesday, U.S. Attorney General Merrick Garland became the most recent international dignitary to visit Ukraine, reiterating Washington's determination to find, arrest, and prosecute anyone responsible for war crimes during Russia's invasion.

Heavy Fighting 

In some of the deadliest combat seen in Europe since World War II, Russia has made gradual progress in the Donbas since April in a struggle that has claimed the lives of tens of thousands of soldiers on both sides.

Some fighting has occurred across the river Siverskyi Donets, which winds through the Donbas, with Russian forces primarily on the east bank and Ukrainian forces primarily on the West.

Despite weeks of severe bombing, the Ukrainian army and an estimated 500 people are still holding out at a chemical facility in the east bank city of Sievierodonetsk.

The governor of the Luhansk region, Serhiy Gaidai, stated that Russian soldiers now held Toshkivka, a village on the west bank further south. This could increase Moscow's aspirations of isolating Lysychansk from territory controlled by Ukraine.

Rodion Miroshnik, the ambassador to Russia of the self-proclaimed pro-Moscow Luhansk People's Republic, stated that forces were "moving from the south towards Lysychansk," with firefights breaking out in several towns.

According to an online post by the regional governor, at least 15 civilians were killed by Russian shelling in the Kharkiv region of Ukraine.

In response to a Ukrainian strike on gas production platforms in the Black Sea, Russia's defense ministry reported that its missiles struck an airport near the port of Odesa.