Russian officials have described a major Ukrainian drone operation targeting areas around St Petersburg as an unprecedented assault, coinciding with the closing day of the country's main annual economic gathering.

Authorities in the Leningrad region reported that more than 140 drones were intercepted, while St Petersburg officials for the first time since the conflict began over four years ago advised citizens to remain indoors.

Ukraine's president confirmed that his forces struck Russian weapons storage sites and a naval installation, framing the action as a legitimate reply to ongoing Russian strikes.

The developments follow comments by Vladimir Putin at the forum dismissing any immediate prospect of direct discussions with Volodymyr Zelensky.

A Ukrainian unit commander told the BBC that reaching objectives inside Russia has become straightforward due to minimal opposition.

The commander of the 413th regiment noted that operations proceed with little difficulty and limited resistance when approaching designated sites.

The Leningrad governor confirmed a blaze at a military site after the strikes and ordered evacuations, while noting only minor damage to some structures.

Zelensky stated that the drones traveled roughly 1,000 km to reach targets including naval facilities in Kronstadt, home to the Baltic Fleet headquarters.

He added that an oil storage site in the Krasnodar region, about 500 km distant, was also struck as part of efforts to impose long-range pressure on Russian capabilities.

The Ukrainian leader called for an end to the fighting but accused Moscow of preferring continued conflict.

The latest wave follows earlier drone activity near St Petersburg just as the investment forum was starting earlier in the week.

The event attracted participants from numerous countries, including a modest American delegation marking the first such presence in years.

In a recent public message, Zelensky urged a halt to hostilities and direct talks with Putin, warning against delaying action until external attention returns.

Putin responded at the forum by rejecting a meeting and insisting that any pause would merely allow Ukrainian forces to regroup.

He reiterated that fighting would continue until Russian objectives are achieved.

Moscow maintains that Ukraine must cede the Donetsk, Luhansk, Kherson and Zaporizhzhia regions and drop NATO aspirations.

Kyiv has rejected territorial concessions, arguing they would encourage further aggression.

In Russian-controlled parts of Luhansk, local administrators have halted bus services on major routes due to repeated drone attacks on supply lines.

Residents were advised to avoid those roads for safety, and rail services plus group transport for children were also restricted.

Putin has claimed full authority over the self-declared Luhansk republic.

Ukraine has intensified drone operations against logistics targets in occupied zones in recent weeks.

Analysts report that hundreds of supply vehicles and dozens of fuel tankers have been hit since early May.

Over four years of war, Ukraine has expanded its domestic production of unmanned systems.

Kyiv now regularly reaches targets deep inside Russia, focusing on energy and fuel infrastructure viewed as supporting the military effort.

Russia continues to accuse Ukraine of deliberately striking civilian sites.