The next phase of the Russia-Ukraine war appears — finally — to be underway.

After months of a near-stalemate, Russian forces on Monday launched another massive missile barrage at key targets in Ukraine, the second such attack in just the past three days. Officials in Kyiv, meanwhile, signaled that a weekend drone strike on an oil depot in Crimea — a portion of Ukraine that Russia forcibly annexed in 2014 and a staging ground for Russian troops in the current war — was the precursor to a long-awaited counteroffensive designed to first degrade the Russian war machine and then push invading troops out of the country entirely.

Taken together, the developments suggest that the nature of the war is about to shift dramatically. Success is far from guaranteed, but the Ukrainian counteroffensive could mark a turning point that puts Moscow on its heels and perhaps opens the door for a goal that once seemed impossible:the recapturing of all Ukrainian territory seized by Russia and its proxy forces.

“Undoubtedly, H-Hour (the time set for a planned attack) for the forthcoming Ukrainian offensives is drawing near,” Mick Ryan, a retired Australian army general and adjunct fellow at the Washington-based Center for Strategic and International Studies, said in a Twitter post late Sunday.

“The Ukrainian military has been preparing for its offensives for some time, and they are clearly ready to force the Russians out of as much of Ukraine as possible,” he said.

Ahead of its high-stakes military campaign, Ukraine received fresh rhetorical backing from Washington on Monday. House Speaker Kevin McCarthy in a visit to Israel reiterated his support for continuing U.S. aid to Ukraine despite a push from some of the most conservative members of his caucus to pull back on Ukrainian assistance and focus on U.S. needs at home.

American military and financial aid has been crucial to the Ukrainian resistance so far. U.S.-made artillery and other equipment helped Ukraine last fall recapture key cities such as Kherson and Kharkiv from Russian control. Mr. McCarthy’s strong comments Monday indicate the GOP-led House intends to keep the aid flowing at a pivotal moment in the war, even if it makes the Biden administration work harder to justify the aid.

The speaker has said he doesn’t believe in giving Kyiv a “blank check” and wants oversight of Ukrainian aid, but he laid into the Russian government during a press conference in Jerusalem.

“I vote for aid for Ukraine. I support aid for Ukraine. I do not support what your country has done to Ukraine. I do not support your killing of children, either,” Mr. McCarthy told a Russian reporter while traveling in Israel. “You should pull out, and I don’t think it’s right, and we will continue to support [Ukraine] because the rest of the world sees it just as it is.”

His condemnation drew applause from a bipartisan U.S. delegation that traveled to Israel this week.

Back in Washington, officials detailed the estimated costs Russia already has suffered in its 14-month war in Ukraine. White House National Security Council spokesman John Kirby said that just since December Russia has suffered 100,000 casualties, including more than 20,000 killed.

“It’s three times the number of killed in action that the United States faced on the Guadalcanal campaign in World War II and that was over the course of five months,” Mr. Kirby said.

U.S. and Ukrainian officials say Russian forces have been badly depleted by a stalemated campaign to take the provincial town of Bakhmut. Col. Gen. Oleksandr Syrskyi, the head of Ukrainian ground forces, told the Associated Press that Russian forces continued to exert “maximum effort” to take Bakhmut but that Kyiv’s defenses have held.

“In some parts of the city, the enemy was counterattacked by our units and left some positions,” he said.

Mr. Kirby would not offer an estimate how many Ukrainian troops have been killed or wounded in the fighting. Joint Chiefs of Staff Chairman Gen. Mark A. Milley said in November that Ukrainian casualties were probably close to the Russian losses so far.

Preparing for battle

Those casualty figures could soon rise even higher, as Ukrainian officials have left little doubt that their spring counteroffensive campaign is on the immediate horizon, hoping to build on battlefield gains Ukrainian forces made before the winter of 2022 set in.

The weekend drone strike on Russia’s oil depot in Crimea may have offered a sneak peak at the tactics Ukraine will employ over the coming days and weeks. Officials suggested that Ukraine will mount a concerted effort to crush Russia’s logistical capabilities, communication systems and supply lines ahead of the counteroffensive.

“The fact that the enemy’s logistics are undermined … this work is preparatory for the broad, full-scale offensive, which everyone expects,” said Natalia Humeniuk, a spokesperson for Ukraine’s southern command, according to English-language media accounts of her remarks to Ukrainian media.

“Therefore, the enemy feels that his resources are undermined and begins to maneuver,” she said.

Ukraine has offered few clues about exactly what the counteroffensive campaign will look like, though President Volodymyr Zelenskyy and other top officials have stressed they intend to recapture all Ukrainian ground, including Crimea, which Russian President Vladimir Putin unilaterally annexed in 2014. U.S. military officials have cautioned that retaking Crimea is a lofty goal and one that would surely require a long, bloody slog.

Beyond that broad objective, Ukrainian leaders have given no clear indications whether their attack will strike east into the disputed Donbas region or make a feint toward the Sea of Azov to the south, effectively cutting off the Kremlin’s vaunted “land bridge” connecting Crimea to Russia proper.

A successful drive to the south in the Zaporizhzhya region would divide Russia’s occupied lands in two and put Crimea, the Russian naval base in Sevastopol and the Kerch Strait bridge all within range of Ukrainian artillery.

In a series of Twitter posts analyzing the coming counteroffensive, Mr. Ryan said reclaiming territory is a key way to gauge the effectiveness of the operation.

“Ukraine takes back its territory (tactical and operational, but with political ramifications). This might seem obvious, but this needs to be an explicit measure of success,” he said.

But Russia is making its own military moves. A major missile barrage Monday struck the eastern Ukrainian city of Pavlohrad, wounding at least 34 people. Missiles fired at Kyiv were intercepted by Ukrainian defense systems, officials said.

Russian officials claimed that the attacks had a military objective, hitting ammunition and fuel stocks and preventing three Ukrainian brigades from deploying for battle. “The objectives of the strike were achieved,” the Russian Defense Ministry said in a statement. “The work of enterprises making ammunition, weapons and military equipment for Ukrainian troops has been disrupted.”

There was no independent confirmation of the Russian claim.

Beyond its missile attacks, Russia’s focus seems to have turned to fortifying its defenses in eastern Ukraine and in Crimea.

“Since summer 2022, Russia has constructed some of the most extensive systems of military defensive works seen anywhere in the world for many decades,” the British Ministry of Defense said in a Twitter post Monday. “These defenses are not just near the current front lines but have also been dug deep inside areas Russia currently controls.”

• This story is based in part on wire service reports.

• Tom Howell Jr. can be reached at thowell@washingtontimes.com.

• Ben Wolfgang can be reached at bwolfgang@washingtontimes.com.