The attack on Vladimir Putin’s hometown, which hosts the showcase annual economic forum set to begin Wednesday, was the latest signal from Kyiv that it can strike deep inside enemy territory and embarrass the Kremlin.

Ukraine launched hundreds of drones at Russian targets early Wednesday, sending black smoke rising above the historic heart of St. Petersburg just as the event dubbed “Putin’s Davos” was due to get underway in the city.

The attack on President Vladimir Putin’s hometown, which hosts the flagship annual economic forum, was the latest signal from Kyiv that it can strike deep inside enemy territory and embarrass the Kremlin.

With peace talks deadlocked and battlefield progress stalled, the two sides have been exchanging intensifying aerial attacks.