By Olena Harmash and Tom Balmforth
KYIV (Reuters) -Ukraine said on Friday its troops had broken through Russia's first line of defences in several places, though they then encountered even more heavily fortified Russian positions.
Deputy Defence Minister Hanna Maliar said Kyiv's troops, in a much-vaunted counteroffensive against Russian forces, were advancing in the Zaporizhzhia region. Washington also said on Friday that Kyiv had made notable progress on the southern front in the last 72 hours.
"There is an offensive in several directions and in certain areas. And in some places, in certain areas, this first line was broken through," Maliar told Ukrainian television.
She added, however, that Kyiv's troops who have been battling to advance through heavily mined areas for almost three months had now run into major defensive Russian fortifications.
"Our armed forces have to overcome a lot of obstacles in order to move forward," she said.
Heavy fighting swept the villages around Bakhmut in eastern Ukraine, captured in May by Russian forces after months of battles, Maliar said but added it was difficult to determine whether any advances had been made.
"In the course of a single day, positions between the two sides can change several times."
The General Staff of Ukraine's Armed Forces in its evening report on Facebook said that Russian forces had made no headway in attempts to advance in five different sectors of the front -- from Kupiansk in the northeast to different parts of Donetsk region.
In Washington, White House National Security Council spokesman John Kirby said the United States had "noted over the last 72 hours or so some notable progress by Ukrainian armed forces ...in that southern line of advance coming out of the Zaporizhzhia area".
"They have achieved some success against that second line of Russian defences", Kirby said, adding it was up to Ukraine how to capitalize on that success.
Ukraine's counteroffensive has not yet recaptured any major settlements, though it has retaken more than a dozen small villages. Last week it captured the village of Robotyne, beyond which lies Russian-occupied high ground, huge anti-tank ditches and lines of concrete fortifications visible from space.
Russia already calls the Ukrainian push a failure; Kyiv says it has been advancing slowly on purpose to minimise losses, and that its task is more difficult because it lacks the air power that its Western allies take for granted.
Kyiv bristled this week over news reports quoting unidentified U.S. officials complaining about its slow progress. Some fear the West's staunch support could begin to falter as colder and wetter weather further hampers progress on the battlefield later this year.
Ukrainian President Volodymyr Zelenskiy is expected to attend the annual gathering of world leaders at the United Nations in New York this month and take part in a U.N. Security Council meeting on Ukraine, Albania's U.N. Ambassador Ferit Hoxha told reporters on Friday.
In an interview in Kyiv on Friday, senior presidential adviser Mykhailo Podolyak told Reuters that for now any negotiations with Russia would amount to a "capitulation" for both Ukraine and the democracies that support it.
He said Ukraine's Western allies, who have poured in billions of dollars of weaponry to help the counteroffensive, understood there could be no kind of "compromise" with Moscow in the war.
"At the moment, the partners understand that this war will no longer end in a compromise solution - that is, either we destroy Russia's capabilities by military means, and to do this we need the appropriate tools, or this war with such level of aggression will continue for some time."
(Reporting by Tom Balmforth and Olena Harmash in Kyiv, Trevor Hunnicutt, Humeyra Pamuk and Susan Heavey in Washington, Ron Popeski in WinnipegEditing by Peter Graff and Cynthia Osterman)