Ukrainian forces have intensified assaults across the Dnieper River near the southern city of Kherson, carrying out raids into Russian-controlled territory on the eastern bank. The increased activity has prompted speculation among analysts and in Russian military circles that Ukraine might be planning a more ambitious effort to open a new front in the war.

In recent days, Western military analysts have cited geolocated video footage that shows Ukrainian forces operating in locations deeper behind enemy lines than previously witnessed.

“Ukrainian actions appear to be larger than previously observed tactical raids,” analysts at the Institute for the Study of War, a Washington-based research institute, said Thursday night.

The Ukrainian military has remained largely silent on the amphibious operations into Russian-held territory near Kherson, and the extent of its ambitions with the river crossings are unknown. In the past, Ukrainian attacks across the river have been limited in scope and duration, with multiple goals, including reconnaissance, sabotage and attacks aimed at undermining Russian defenses and logistical operations.

But President Vladimir Putin of Russia, speaking to reporters during his trip to Beijing this week, indicated the Kremlin believes the new assaults are more ambitious, claiming that they were part of the “next counteroffensive.”

If Ukraine can manage to establish a secure position across the Dnieper, it would put Russian targets in Crimea at greater risk, allow Ukrainians to further compromise Russian logistics, and create a new front in an area where Russian fortifications are less comprehensive and minefields are believed to be less dense.

The potential promise of any such effort is matched by the peril it holds. Over centuries of warfare, rivers have proved to be among the most challenging natural barriers for an attacking army. But crossings by boat are the only option for Ukraine; the major bridges linking Kherson city to the eastern bank were destroyed by bombing.

Oleksandr Tolokonnikov, a spokesperson for the Kherson military administration, said that Ukrainian forces are “constantly working on landing marines and others” on the eastern banks of the river. And although he could not talk about specific operations, he cited increased Russian aerial bombardments in the area as evidence of the Kremlin’s concerns about the situation.

“If you look at yesterday, there were 24 aerial bombs,” he said.

A month ago, the Ukrainian military was seeing one or two powerful 500- and 1,000-pound guided aerial bombs every day. That number over the past week has risen to about 20, he said. They have often landed in areas populated with civilians, he said, killing and injuring dozens.

The cross-river activity comes as Ukraine hopes to take advantage of newly supplied long-range missiles provided by the United States to target Russian air bases, ammunition depots and command centers in southern Ukraine, long out of reach of most Ukrainian weapons.

High-resolution satellite imagery showed the aftermath of the first strikes this week at two Russian air bases in occupied Ukraine involving the newly acquired Army Tactical Missile System. The imagery indicated that at least 14 Russian helicopters had been damaged or destroyed, according to military analysts, expanding on initial claims by Ukraine that at least nine aircraft were damaged or destroyed.

One of the air bases, in Berdiansk, is a primary forward operating base for Russian forces in the south. The extensive damage there most likely will “have an impact on Russia’s ability both to defend and conduct further offensive activity” in the region, the British military intelligence agency said Friday.