In a new sign that the war in Ukraine is also now a war inside Russia, Kyiv in the early hours of Monday morning struck military targets deep within Russia. It appeared likely that the aim of the attacks was the disruption of Russia’s ongoing bombing campaign against Ukraine infrastructure targets. 

Early on  Monday, Russian media reported two explosions at air bases in Russia. One reportedly happened at a base that houses nuclear-capable strategic bombers that have been involved in launching strikes against Ukraine.

Neither Ukrainian nor Russian authorities immediately commented on the possible cause of the blasts. Russian state news agency RIA Novosti said three servicemen were killed and six were injured and a plane damaged when a fuel truck exploded at an air base at Ryazan, in western Russia. The base houses long-range flight tankers that serve to refuel bombers in the air.

Separately, authorities in the Saratov region along the Volga River said they were checking reports about an explosion in the area of the Engels air base, which houses Tu-95 and Tu-160 strategic bombers that have been involved in launching strikes on Ukraine. Those bombers are capable of carrying nuclear weapons.

The Saratov regional governor, Roman Busargin, said there was no damage to civilian facilities. Regional media reported sounds of a powerful explosion near the Engels base, and some residents were quoted as saying they saw a flash of light coming from the area.

Asked whether President Putin had been briefed about the Engels base explosion, the Kremlin spokesman, Dmitry Peskov, said simply the president was regularly informed of ongoing developments.

Ukraine’s air force meanwhile said Monday it shot down more than 60 of about 70 missiles that Russia fired in its latest barrage against Ukraine. It was part of Moscow’s new, stepped-up campaign that has largely targeted Ukrainian infrastructure and disrupted supplies of power, water, and heat as winter looms.

Early indications showed Russia fired 38 cruise missiles from ships in the Caspian Sea and from the southern Russian region of Rostov. Another 22 Kalibr cruise missiles were fired from its Black Sea fleet, Ukraine’s air force said on its Telegram page. The attack also involved Russian long-range bombers, fighter jets, and guided missiles, it said. “In total, more than 60 invaders’ missiles were shot down,” the statement said. 

Russia’s missile attacks  across Ukraine on Monday struck homes and buildings, killing civilians and disrupting electrical power that caused blackouts and cut water supplies for the Black Sea port of Odessa.

Mr. Putin, meanwhile, drove a truck across a bridge linking his country to the Crimean Peninsula following its repair after a bombing in October that had embarrassed Moscow.

Mr. Putin’s journey across the bridge over the Kerch Strait was an important sign that Russia was able to repair the span quickly after the October 8 truck bomb that severed a key link from Crimea to the mainland. He also spoke to workers and discussed the repairs with a senior government official responsible for the project.

The attack disrupted travel on one of the two automobile sections of the bridge to Crimea, which Russia annexed in 2014. Russia blamed Ukrainian military intelligence and responded with waves of strikes on Ukraine’s energy facilities and other key infrastructure

Ukrainian authorities have been anticipating Monday’s missile barrage for days. The country’s electricity provider, Ukrenergo, lashed out at Russia over “the eighth massive missile attack by a terrorist country,” saying its facilities had been hit, triggering blackouts. It urged residents to stay in shelters as its crews tried to repair the damage.

In the capital of Kyiv, scores of people quickly congregated in the central Zoloti Vorota metro station after the warnings, and many checked their phones for updates. There were no immediate signs whether the city or the surrounding region was hit.

Air raid sirens sounded across the country. Ukrainian media reported explosions in several parts of the country south of Kyiv, including Cherkasy, Kryvyi Rih, and Odessa, where the water company said power was out to pumping stations, leaving the city without water. “The enemy is again attacking the territory of Ukraine with missiles,” the deputy head of the Ukrainian president’s office, Kyrylo Tymoshenko, wrote on Telegram.

Mr. Tymoshenko said two people were killed and three others injured — including a 22-month-old child — in the village of Novosofiyivka in the southern Zaporizhzhya region.

A Ukrainian air force spokesman, Yuriy Ihnat, said land-based missiles were launched from southern Russia and missiles were fired from ships in the Caspian and Black seas. Russian strategic bombers also launched missiles, he said.

Today’s counterstrikes at Russian bases, beyond their strategic value to Ukraine, will have the psychological effect of striking fear close to Moscow. Elsewhere in Russia, defensive fortifications have recently sprung up to help deter anticipated Ukrainian retaliatory strikes. Monday’s attacks underscore Russia’s growing vulnerability as the war teeters toward the 10-month mark.