Heavy fighting between Ukrainian and Russian forces is under way in parts of eastern Ukraine and the northeast Kharkiv region as Moscow continues a crackdown on protests against a partial mobilization decreed by President Vladimir Putin last week.
President Volodymyr Zelenskiy said the eastern Donetsk region remained Ukraine's -- and Russia's -- top strategic priority, with fighting under way in several towns as Russian troops try to advance to the south and west.
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Zelenskiy said in his nightly video address on September 26 that the military situation in Donetsk was "particularly severe."
"We are doing everything to contain enemy activity. This is our No. 1 goal right now because Donbas is still the No. 1 goal for the occupiers," Zelenskiy said.
Regional officials, meanwhile, said that Russia carried out at least five attacks on targets in the Odesa region using Iranian drones in the last few days.
Russian missiles targeted the airport in Kriviy Rih in central Ukraine, destroying infrastructure and making the airport unusable, Valentyn Reznichenko, governor of Dnipropetrovsk region, said on Telegram.
The Ukrainian armed forces' southern command said on September 27 that its counteroffensive in the southeastern Kherson region had resulted in enemy losses of 77 servicemen, six tanks, five howitzers, three anti-aircraft installations and 14 armored vehicles.
The claim could not be independently verified.
Fighting was also raging in the Kharkiv region in the northeast, which has been the target of a Ukrainian counteroffensive this month.
In the south, Ukrainian forces pressed on with a campaign to render four bridges and other river crossings inoperable to disrupt supply lines to Russian forces.
The General Staff of the Ukrainian Armed Forces reported on September 27 that Russian forces used drones, including Iranian-made Shahed-136 drones, in the northeastern Donetsk region to conduct reconnaissance.
Russian troops also launched two missile and six air strikes in the region and carried out more than 20 attacks from rocket systems on military and civilian objects, the General Staff's evening report said.
The Ukrainian Air Force responded by carrying out 10 strikes, hitting Russian troops and military equipment, the General Staff said. The air force also destroyed one Su-25 aircraft and five drones of various types, the report said. These claims could not be verified.
Security Council Secretary Oleksiy Danilov told RFE/RL that Ukraine will continue to defend itself even in the face of Putin's veiled threats that it could use nuclear weapons.
In the event of such an "audacious" attack, Danilov said if even there is no response from the world community or NATO countries, "this does not mean that we will not defend our land."
Danilov said the Security Council has developed detailed instructions for citizens in the event of Russia's use of tactical nuclear weapons and intends to "publicize them as much as possible" in the coming days.
In Russia, the announced mobilization of some 300,000 reservists has sparked the first sustained protests since the start of the unprovoked invasion on February 24.
OVD-Info, a human rights group that monitors political arrests in Russia, said that 2,386 people had been detained by September 26. All public criticism of Russia's "special military operation" is banned.
In Geneva, the United Nations voiced alarm on September 27 at the report.
"We are deeply disturbed by the large number of people who have reportedly been arrested," UN High Commissioner for Human Rights spokeswoman Ravina Shamdasani told reporters.
Citing unidentified officials, two Russian news sites that operate from abroad -- Meduza and Novaya gazeta Europe -- reported that the authorities were planning to ban men from leaving as cars clogged border checkpoints, with reports of a 48-hour queue at the sole road border to neighboring Georgia, which allows Russian citizens to enter without a visa.
Asked about the prospect of the border being shut, Kremlin spokesman Dmitry Peskov told reporters on September 26: "I don't know anything about this. At the moment, no decision has been made on this."
In Washington, White House spokeswoman Karine Jean-Pierre said the United States will consider asylum applications from Russians fleeing mobilization.