Ukrainian President Volodymyr Zelenskiy said in a video message late on July 6 that artillery that Ukraine has received from Western partners has had an effect on the battlefield.
"Finally, it is felt that the Western artillery -- the weapons we received from our partners -- has worked very powerfully,” he said, praising its accuracy.
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The Ukrainian military has inflicted “very noticeable blows on warehouses and other points that are important for the logistics of the occupiers,” he said. “And this significantly reduces the offensive potential of the Russian Army.”
Ukrainian forces are currently advancing in several directions, including in the south in the regions of Kherson and Zaporizhzhya, he said.
"We are fighting for our entire south, for the entire Ukrainian Donbas," he said, noting a "most brutal confrontation" near Slovyansk and Bakhmut and adding that Ukrainian forces also are fighting for the Kharkiv region.
"Let the occupiers not think that their time on this land is long, and the superiority of their artillery is eternal," Zelenskiy said.
Ukrainian Foreign Minister Dmytro Kuleba said on Twitter that he spoke with U.S. Secretary of State Antony Blinken on July 6, and they "coordinated steps to accelerate the delivery of heavy weapons from the U.S. and other partners."
Kuleba said he had a similar conversation with German Foreign Minister Annalena Baerbock in which he emphasized the urgent need to increase supplies of German self-propelled howitzers and multiple-launch rocket systems (MLRS) to Ukraine.
Ukrainian officials earlier called on civilians to urgently evacuate the city of Slovyansk and other parts of the Donetsk region as Russia escalates its offensive in the east.
Pavlo Kyrylenko, head of the Donetsk regional military administration, said in a Telegram post that two people died in the city of Avdyivka, which is north of the regional capital.
The Donetsk cities of Slovyansk, Krasnohorivka, and Kurakhove each reported one civilian killed on July 6.
Slovyansk has been subjected to "massive" Russian bombardment in recent days, with at least two people killed and seven others wounded in an attack on a marketplace on July 5, officials said.
"Russia has turned the entire Donetsk region into a hot spot where it is dangerous to remain a civilian," Kyrylenko said on Telegram. "I call on everyone to evacuate. Evacuation saves lives."
Moscow-backed separatists in the region said attacks by Ukrainian forces killed four civilians. The claims could not be independently verified.
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Deadly Russian Strike Hits Market In Eastern Ukraine's Slovyansk
An intelligence report from the British Defense Ministry on July 6 said that "there is a realistic possibility that the battle for [Slovyansk] will be the next key contest in the struggle for the Donbas."
"Russian forces from the Eastern and Western Groups of Forces are likely now around 16 km north from the town of [Slovyansk]," the intelligence report said.
Speaking on July 6, officials said Ukraine had so far thwarted an attempted Russian advance into the north of the Donetsk region. Russia-backed separatists and Russian forces are already in control of the southern part of the Donetsk region.
"We are holding back the enemy on the border of Luhansk region and Donetsk region," Luhansk regional governor Serhiy Hayday told Ukrainian television.
He said Russian regular army and reserve forces had been sent there in an apparent effort to cross the Siverskiy Donets River and that two small settlements just inside Luhansk's borders were the scene of fierce fighting.
"Luhansk region even now is fighting. Almost all the territory has been captured, but in two settlements fighting is ongoing" he told a video briefing.
Vadym Lyakh, the mayor of Slovyansk, told a video briefing on July 6 that the city had been shelled for the last two weeks.
"The situation is tense," he said.
The southern port city of Mykolayiv was also being heavily shelled, Oleksandr Senkevych, its mayor, told a briefing. Russian forces were using multiple-launch rocket systems to shell the city, which has shed about half of its prewar population of half a million people, he said.
"There are no safe areas in Mykolayiv," he said. "I am telling the people of the city that they need to leave."
To the north of Donetsk, Russian forces also hit Kharkiv, Ukraine's second-largest city, with missile strikes overnight, the regional governor said on July 6 on Telegram.
Three districts of the city were targeted, Oleh Synyehubov said. Three people, including a toddler, sustained injuries, he added.
Russia's Defense Ministry said its forces killed up to 100 Ukrainian troops and destroyed four armored vehicles in Kharkiv, and in the Mykolayiv region struck a Ukrainian air-defense radar and a camp housing foreign fighters.
Ministry spokesman Igor Konashenkov said air-launched high-precision missiles also destroyed two HIMARS multiple-launch rocket systems sent by the United States along with ammunition for the systems. The Ukrainian military denied Moscow's claims.
Zelenskiy, speaking at a briefing in Kyiv with visiting Irish Prime Minister Micheal Martin, said the terms of how the war will end depend on international sanctions pressure on Russia and the supply of weapons to Ukraine.
Irish Prime Minister Micheal Martin (left) and Ukrainian President Volodymyr Zelenskiy hold a press conference in Kyiv on July 6.
He said the answer to how long the war will last depends on "how quickly we can make Russia think about peace because we believe that they have not even begun to think about it."
Russia has yet to feel the effects of powerful sanctions in part because "unfortunately, there are still some allies who help the Russian Federation or their business," he added.
Martin used the visit to restate Ireland's full backing for continued sanctions against Russian President Vladimir Putin's regime and for Ukraine's path to membership in the European Union.
"I am grateful that Ireland stands by our side in this crucial time for our country," Zelenskiy told Martin.
Ireland has taken in more than 36,000 Ukrainian refugees and has given 20 million euros ($20.4 million) in humanitarian support and assistance to the country in addition to health equipment and medical donations worth more than 4.5 million euros.