DONETSK, Ukraine — Ukrainian forces battered the outer edges of the rebel stronghold of Luhansk on Sunday, pushing deeper into the city but falling short of retaking it.
The Ukrainian forces hit rebel positions in an area called Yuvileiny in western Luhansk, a rebel spokeswoman and residents said. Some accounts said the forces had established a checkpoint there, although a Ukrainian military spokesman could not confirm that.
Some news reports said the government forces had retaken the city. But residents and rebels said Sunday evening that the city was still in rebel hands.
“So far our forces are holding them back,” said a spokeswoman for the self-declared Luhansk People’s Republic who asked not to be identified by name for her safety.
Andrei Anoshin, a journalist for Realnaya Gazeta, a newspaper in Luhansk, said that the city had been shelled intensely for the past week and that many civilians had been killed.
“Today wasn’t that different from other days,” Anoshin said, adding that in the city center, “it is tense, but militarily calm.”
The military advances came as relations between Ukraine and Russia fell to a new low. On Sunday, a Russian citizen was killed on Russian soil by what the Russian government said was an errant Ukrainian shell. Ukraine denied firing a shell into Russian territory.
Russia said the shell hit the courtyard of a residential building in the Russian town of Donetsk — near the Ukrainian city of the same name that has become a rebel stronghold — early on Sunday.
A spokesman for President Vladimir Putin of Russia called the episode a provocation and said it could have “irreversible consequences.”
Also on Sunday, Putin met with Chancellor Angela Merkel of Germany in Brazil, where they are attending the World Cup final, and discussed the Ukraine crisis.
Citing a Putin spokesman, Reuters said the two leaders had called for the resumption of political negotiations on Ukraine but had added that for this to happen, a cease-fire must be declared and honored by all sides.
Ukraine’s president, Petro Poroshenko, declared a unilateral cease-fire last month but then called it off, saying the rebels had refused to abide by it and had used the truce merely to regroup and rearm.
Ukraine is trying to quell a pro-Russia insurgency that has inflamed its southeastern edge since spring. Luhansk, a region of coal mines and industry that is poorer and grittier than Donetsk, is critical for the insurgents because it shares a long border with Russia, which the West believes is quietly supporting the rebels.
Ukraine has been hitting rebel positions for days and has gained considerable ground in areas south and west of the city.
The Russian news agency Interfax cited an unnamed rebel in Luhansk as saying the Ukrainian forces had begun to storm the city from an area called Alexandrovka.
The rebel said the attack included not only artillery fire, but also dozens of tanks and two fighter helicopters. It was impossible to verify the report. Three residents interviewed Sunday said they had seen neither tanks nor helicopters.
In Donetsk, a local emergency worker, Alexander Ryaboshapka, said seven people were killed Saturday in a rocket attack in the Petrovsky neighborhood. One of them was a young girl. The Ukrainian military denied responsibility for the attack.
The rockets landed in such a way that suggested that they had been fired from the south, where Ukrainian forces are based. Still, some residents said on Sunday the rockets had been fired from rebel positions.
Putin spokesman Dmitry Peskov told Russian news agencies Putin and Merkel indicated in their meeting that they believe the situation in east Ukraine was deteriorating.