ST. PETERSBURG, Russia - A thick black smoke cloud billowed over the St. Petersburg horizon after a Ukrainian drone hit, creating a somber atmosphere for the start of President Vladimir Putin's yearly display of Russia's economic successes.

As Putin was due to reach his native city on Thursday for the St. Petersburg International Economic Forum, the prior day's Ukrainian strike that ignited an oil terminal represented another awkward setback to his attempts to downplay the effects of the ongoing four-year conflict and portray it as unrelated to everyday Russian life.

The assault, which also struck a naval installation near Russia's second-largest city on the Gulf of Finland, highlighted Ukraine's increasing ability to reach far into its neighbor and showed that even the well-defended birthplace of Putin faces rising risks.

Numerous flights faced delays or rerouting at St. Petersburg's airport while officials restricted cellphone internet access in an effort to block further drone operations.

Putin had reduced the scale of Russia's annual Victory Day parade on May 9 due to concerns over possible Ukrainian drone strikes. Shortly afterward, a large drone assault on Moscow's outskirts claimed three lives and exposed the capital's exposure.

Kremlin spokesman Dmitry Peskov stated that Russian forces are advancing inside Ukraine "in order to prevent such attacks" like the one on St. Petersburg. He added that the "systematic" strikes on Kyiv, which Russia had warned about last week, are now in progress.

On Tuesday, Russia targeted Kyiv and additional Ukrainian cities using hundreds of drones and dozens of missiles, resulting in 23 deaths and 151 injuries.

Putin has relied on the forum to promote his nation's economic gains and draw foreign investment. Frequently presented as Russia's counterpart to the World Economic Forum in Davos, Switzerland, the event typically attracts tens of thousands of delegates globally.

Although Western officials and executives have avoided the forum since Putin launched troops into Ukraine in 2022, Russia has aimed to draw more participants from other areas to support its stated aim of fostering a "multipolar world."

Saudi Arabia, serving as a special guest this year, has dispatched a sizable group. The presidents of Uzbekistan and Tanzania along with China's vice president are also present. A U.S. official, Rodney Mims Cook Jr., leader of the U.S. Commission of Fine Arts, will join the gathering for the first time in years.

Russia's economic prospects have dimmed as the early lift from heavy military outlays has faded. The government has increased taxes and expanded domestic borrowing to maintain control over its budget shortfall.

Putin is likely to play down Russia's economic difficulties during his forum appearance, yet the Ukrainian strike on St. Petersburg's port roughly 15 kilometers from the event site has emphasized the mounting pressures from the conflict.

Hours before the forum began on Wednesday, Ukrainian drones also struck the Kronstadt naval base on an island in the Gulf of Finland, home to Russia's Baltic Fleet since Peter the Great established St. Petersburg. While most of the fleet has relocated to Russia's Baltic exclave of Kaliningrad, Kronstadt keeps its symbolic value as the center of the country's naval heritage, featuring its historic cathedral and aged fortifications.