Ukraine's public air raid alert app was reportedly hacked Sunday night, disseminating false warnings of radiation and chemical threats to residents in Kyiv and other areas. The Ukrainian Air Force confirmed the app appeared to be influenced by the "enemy" and urged citizens to remain calm.

"There is no radiation threat! Stay calm and follow our updates on our channel!" the air force stated on Telegram, according to the Daily Mail. Spokesman Yuriy Ignat confirmed the app had been hacked.

The fake alerts began around 10:47 p.m. local time, with messages indicating "Radiation threat declared in Kyiv," followed by warnings of a potential "nuclear alert across Ukraine" and a "chemical attack on Kyiv." Other messages mentioned a "Street fighting threat" in the capital. Multiple all-clear notifications were later issued.

The Ukrainian Centre for Countering Disinformation stated that the information broadcast by the application did not correspond to reality. SPRAVDI, Ukraine's Center for Strategic Communications, attributed the hack to Russia.

This incident occurred shortly after the conclusion of a localized truce in the eastern Kherson region, which had been the longest ceasefire of the war. Ukrainian officials reported that Russia refused an extension of this truce, which began on Tuesday. While the ceasefire was in effect, neither side reported violations. The truce reportedly enabled a humanitarian mission to the Russian-occupied city of Oleshky.

Despite the temporary de-escalation in Kherson, Ukrainian President Volodymyr Zelensky stated on Sunday that Russia continues to target Ukraine's energy systems in preparation for winter.