As President Volodymyr Zelensky of Ukraine heads to Washington on an urgent mission to rally flagging Western support for his nation, the Russian military on Monday targeted the Ukrainian capital with the most intense salvo of ballistic missiles in months.

Explosions boomed over the snow-covered capital, Kyiv, shortly after 4 a.m.: Missiles racing toward the city at several times the speed of sound had been shot out of the sky even before air alarms could sound and send civilians racing for shelter.

The bombardment came hours after a video circulated on Sunday of President Vladimir V. Putin of Russia, sipping champagne in Moscow and celebrating waning Western support for Kyiv as he declared that Ukraine had “no future.”

All eight missiles aimed at Kyiv, a city of 3.3 million people, were shot down, and 18 Russian attack drones aimed at targets in southern Ukraine were also defeated, the Ukrainian military said. City officials said that at least four people were injured by falling debris in Kyiv.

The attack came just over two weeks after Russian forces targeted Kyiv with 75 drones — the largest number aimed at the capital since Russia launched its full scale invasion nearly two years ago — and less than four days after the Russian Air Force conducted the first major wave of strikes on Kyiv using its heavy bomber fleet in nearly three months.

“This was probably the start of a more concerted campaign by Russia aimed at degrading Ukraine’s energy infrastructure,” Britain’s defense intelligence agency said on social media just hours before Monday’s pre-dawn assault, referring to the recent attacks.