Ukraine’s Air Force said its air-raid warning application, “air alarm,” was hacked after unverified alerts appeared about a possible nuclear threat, “likely compromised by foreign interference.”

Yuriy Ihnat, a spokesperson for the Air Force, confirmed the application was hacked and added, “There is no nuclear threat.”

Ukraine’s Strategic Communications Center, Spravdi, blamed Russia for the hack.

An hour later, Russia’s Ministry of Emergency Situations said the country’s public alert application—which informs people about drone attacks and other threats—was targeted and hackers posted “false information” in the app.

The ministry said its teams were working to address a “large-scale cyberattack” and Russia did not name anyone as responsible.

The two attacks came after the end of the Kherson ceasefire, which was in place from the 5th to the 10th of Aban, and Ukraine says Russia rejected its extension.