Russia is preparing a major new attack on Ukraine, President Volodymyr Zelenskyy said on Friday on Telegram, citing intelligence data.

Speaking later in his nightly video address, Zelenskyy said: “We have intelligence information about Russia preparing a new large-scale strike.”

“Our services are responding promptly and are prepared. The Air Force and other defenders of the sky will work 24/7, as they always do.”

Russia said on Monday it intended to launch “systematic strikes” on targets in Kyiv and warned foreigners and diplomats to leave.

It said the action was in response to a drone strike last week on a dormitory in Ukraine’s Russian-held Luhansk region which killed 21 people. Ukraine denied carrying out the attack.

Russian strikes on Kyiv and other areas of Ukraine last Sunday killed two people and injured dozens.

In a Telegram post, Zelenskyy called for further sanctions on Russia and said the implementation of agreements with partners on air defense must not be delayed.