KYIV, March 30 (Reuters) - Ukraine said on Thursday Russian forces had made some gains inside the eastern battlefield city of Bakhmut, but at a heavy price in lives lost that has blunted Moscow's offensive as Ukraine prepares a counterstrike of its own.
In a potential escalation of Moscow's diplomatic feud with Washington, Russia's FSB security service arrested an American reporter for The Wall Street Journal, Evan Gershkovich, on suspicion of spying for the United States.
The newspaper denied the allegations and demanded the immediate release of its "trusted and dedicated reporter". There was no immediate response from Washington. A U.S. diplomatic source said the embassy had not been informed about the incident and was seeking information from the Russian authorities.
The small mining city of Bakhmut has been the site of the bloodiest battle in Europe since World War Two as Russian forces have sought their first victory since mid-2022 in a huge winter assault.
Ukraine has been on the defensive for nearly five months but says it is planning a counteroffensive soon.
"Enemy forces had a degree of success in their actions aimed at storming the city of Bakhmut," the General Staff of the Ukrainian armed forces said in an overnight report. "Our defenders are holding the city and are repelling numerous enemy attacks."
The report gave no details of the Russian gains. The Institute for the Study of War think tank said Russian troops and Wagner mercenaries had captured territory in the south and southwest of the city over the past two days, and Wagner had occupied a metal plant in its north this week.
Russian forces have been advancing slowly inside Bakhmut in intense street fighting for weeks. A month ago, Kyiv seemed likely to abandon the city but has since decided to stay and fight for it, hoping to break the attacking force.
Deputy defence minister Hanna Malyar said in a social media post that losses were inevitable, but "the enemy's losses are many times greater".
Serhiy Cherevatyi, a Ukrainian military spokesperson, told national television: "Bakhmut remains the epicenter of military activity...It's still constantly 'hot' there."
As winter has turned to spring, the pressing question is how much longer Russia can sustain its offensive, and when or if Ukraine will strike back.
Ukrainian and Western officials point to signs that Russia's campaign is flagging. The number of daily Russian attacks on the front line reported by Ukraine's general staff has declined almost by half over the past four weeks.
Russia's invasion has destroyed Ukrainian cities and set millions of refugees to flight. Tens of thousands of Ukrainian civilians and soldiers on both sides are believed to have died.
Moscow, which says it sent troops because its neighbour posed a security threat, has vowed to press on fighting at least until it controls all the territory of eastern provinces, among five it claims to have annexed. Kyiv says it will fight on until all Russian troops are driven from its land.
'STAND IN SOLIDARITY'
The arrest of the U.S. reporter Gershkovich could have an impact on Russian diplomacy with the United States, and deepen Moscow's isolation by frightening off more of the few foreign journalists who remain.
He is the highest profile American arrested by Russia since basketball star Brittney Griner, who was caught arriving in Moscow with cannabis oil a week before the invasion of Ukraine and freed in a prisoner swap ten months later.
"The Wall Street Journal vehemently denies the allegations from the FSB and seeks the immediate release of our trusted and dedicated reporter, Evan Gershkovich. We stand in solidarity with Evan and his family," the newspaper said.
The FSB said in a statement it had arrested Gershkovich in the Urals industrial city of Yekaterinburg, "suspected of spying in the interests of the American government". It accused him of illegally gathering information about "one of the enterprises of Russia's military-industrial complex", which it did not identify. It provided no evidence.
Kremlin spokesman Dmitry Peskov said he understood Gershkovich had been "caught red-handed". Asked at a briefing if the arrest could provoke a response from Washington towards Russian journalists, he said: "We hope there will be no such thing, and there shouldn't."
The U.S. State Department's travel guidance, last updated in February this year, advises U.S. citizens not to go to Russia because of the danger of arbitrary arrest, and says those living or travelling there should depart immediately.
Moscow has effectively outlawed all independent Russian news outlets since the start of the war but has continued to accredit some foreign reporters. Journalism has become sharply limited by laws that impose long sentences for any public criticism of the war, which Russia refers to as a "special military operation".
Andrei Soldatov, an author and expert on Russia's security agencies who is outside the country, said on social media that Gershkovich was no spy, and his arrest was "a frontal attack on all foreign correspondents who still work in Russia. And it means that the FSB is off the leash."
