Russian President Vladimir Putin's forces have begun their summer offensive in Ukraine despite facing major internal challenges.

In its fourth year since first attacking Ukraine in February 2022, Russia's military continues to show strength in troop numbers, artillery, and missiles.

However, most of the forces are unprofessional and poorly trained, according to The Washington Post. Not only that, intelligence weaknesses and corruption pervade.

Thus, Moscow's military is expected to advance as it moves east, likely gaining several thousand square miles of territory, at a very high cost.

"These [mass assault] tactics are the only thing the Russian military is capable of at the moment. And it's very inhumane because in fact dead people are being traded for territory," independent Russian military analyst Ian Matveev said, the Post reported.

"What we have in the Russian army now is a lot of soldiers, but they have no training."

Russian soldiers have told bloggers and independent reporters that online fundraisers have been used to buy weapons and equipment, but their countrymen are tired of sending money.

"I understand that people are tired of helping the army and tired of the war. I understand why many people have questions about why the army should be helped, but I have no answers to those questions," one Russian military blogger wrote before adding that "right now is a turning point" and soldiers "need help."

Russia launched its biggest aerial attack against Ukraine overnight, a Ukrainian official said Sunday, part of an escalating bombing campaign that has further dashed hopes for a breakthrough in efforts to end the three-year-old war.

Russian forces have been slowly grinding forward at some points on the roughly 620-mile front line, though their incremental gains have been costly in terms of troop casualties and damaged armor.

Also, morale is low, according to bloggers and independent media reports, with desertions and widespread drunkenness and drug abuse rampant among Russian troops.

Corrupt commanders sometimes demand bribes to spare soldiers from deadly assaults, the Post reported. The leaders also punish some soldiers by ordering they be killed or sending them on suicidal assaults.

Bloggers who provide war updates usually avoid criticizing Putin.

"The biggest strength is they have direct contact with the Russian military, with people who are anywhere from the trenches to the Ministry of Defense. They can provide information that no one else has access to," said Russian author Ivan Philippov, who's writing a book about the war's bloggers.

"The biggest issue that they see is not enough manpower. It's been a constant topic for at least a year. They have been talking about how the people who want to fight and who sign contracts now are really — and it's their own words — second-rate citizens, people with alcohol problems, people with drug addiction, people with poor health, people who are over the fighting age. Not all of them, but more and more of them."

The Associated Press contributed to this story.

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