KYIV, Ukraine — Russia unleashed yet another massive aerial bombardment aimed at Ukrainian cities and towns before dawn Monday, pressing its advantage as the United States increasingly removes itself from the conflict and diplomatic efforts to end it.

At least 355 Russian drones swarmed the skies across Ukraine, and bombers unleashed nine missiles, Ukraine said. The attack followed criticism by President Donald Trump of President Vladimir Putin of Russia, whom he accused on social media of going “absolutely CRAZY” in his bid to conquer Ukraine.

But Trump, speaking to reporters before boarding Air Force One on Sunday, gave no indication that he is willing to provide Ukraine with military assistance. He also declined to answer questions about whether the attacks will lead to a change in policy.

Over the past week, Russia has directed at least 1,390 drones and 94 missiles at targets across Ukraine, the Ukrainian air force said. The attacks have killed at least 30 civilians and injured more than 163, Ukraine says.

The campaign comes a week after Trump spoke to Putin by telephone and appeared ready to abandon his efforts to secure a ceasefire.

Russia has clearly seen an opening as the United States — long the main arsenal of Ukraine’s resistance — pulls back from the diplomatic process and resists supplying Kyiv with additional military assistance, according to analysts.

“For the last three years, for both good and ill, the policy choices in Washington had played an active, at times determinative, role in shaping the course of the war,” said Phillips O’Brien, a professor of strategic studies at the University of St. Andrews in Britain. “The U.S. is slowly starving Ukraine of vital aid, which is very much understood and acted on by the Russians.”

Trump’s comments on Russia’s prosecution of the war constituted a sharp rebuke of Putin. “I don’t know what the hell happened to Putin,” Trump said. “I’ve known him a long time. Always gotten along with him. But he’s sending rockets into cities and killing people, and I don’t like it at all.”

But even as Trump condemned the latest Russian bombardments, he also criticized President Volodymyr Zelenskyy of Ukraine, accusing him of “provocative words.”

And, in a comment that appeared to reiterate his earlier expressed desire to step away from trying to mediate the conflict, leaving it for Ukraine and Russia to solve, he said: “This is not Trump’s war.”

The Kremlin spokesperson, Dmitry Peskov, expressed gratitude to Trump for pressing negotiations between Russia and Ukraine, calling the start of talks in Istanbul earlier this month “a very important achievement.”

“This is a very crucial moment, which is associated with an emotional overload for absolutely everyone and with emotional reactions,” Peskov told reporters Monday.

Since taking office, Trump has not approved a single new military assistance package for Ukraine and has not said whether he will spend the $3.85 billion Congress has already authorized for Kyiv.

While the last shipments of weapons promised by the Biden administration are still making their way to the battlefield, no new weapons are in the pipeline. It is unclear if the White House will even allow Ukraine to purchase American weapons any more.

As Ukraine runs out of interceptor missiles for its Patriot systems, Russian bombardments will become more deadly, military analysts have warned.

Meanwhile, Russia continues to upgrade its arsenal. Russian Iskander-M ballistic missiles now deploy radar decoys and follow quasi-ballistic trajectories, making them harder to intercept, according to Ukrainian officials and military analysts.

“For the Patriot system, which is designed to intercept ballistic missiles by calculating the interception point, it becomes much harder to predict that point,” said Yurii Ihnat, the air force’s chief spokesperson.

Valery Zaluzhny, a former top commander of Ukraine’s military who is now ambassador to Britain, on Friday issued a dire warning of what lay ahead for Ukraine.

“I hope there are no more people in this room who still believe in some kind of miracle or wonder — in a white swan that will bring peace to Ukraine, restore the 1991 or 2022 borders, and bring great happiness afterward,” he told a conference of arms dealers in Kyiv.

“As long as the enemy has the resources, the strength and the means to strike our territory and attempt localized offensive actions, they will continue to do so,” he said.

Moscow has been using its main advantage — sheer numbers — to devastating effect. In recent weeks, Russian advances have increased in a pocket of land between Pokrovsk and Kostiantynivka, two linchpins of the Ukrainian defense in the eastern Donetsk region.

To achieve even its minimal goal of occupying the broader Donbas region in the east, Russian forces will have to seize those towns, analysts say. If the past is any guide, that will mean months of bloody battles like those that reduced cities in the region such as Mariupol, Bakhmut and Avdiivka to ashes.

“Last year Ukraine adapted to how Russian forces were fighting by investing in drone units and a systematic approach to reducing the effectiveness of Russian assaults,” said Michael Kofman, a senior fellow at the Carnegie Endowment for International Peace. “This helped stall Russian advances over the winter, sapping any momentum.”

But, he added, “Russia retains a significant manpower advantage, and pressure will increase over the summer as more Russian units are brought in to sustain their push.”