The war in Ukraine has now extended beyond six months, and while one expert said it isn't even close to being over, Ukrainian troops have marked significant advancements in recent weeks.

A massive counteroffensive by Ukraine caused Russian troops to retreat in key areas, which Greater Boston guests Tom Nichols, international affairs expert and staff writer with The Atlantic, and Carol Saivetz, senior advisor for MIT’s Security Studies program, said was unexpected.

Saivetz told Jim Braude that Ukraine's success has shown Russia's lack of preparedness and understanding of the battlefield along with corruption that impacts the military.

Nichols said the counteroffensive is a significant milestone in the war.

"This is a really big deal to have the Russian military fleeing its positions and leaving its equipment behind so fast that the Ukrainians couldn't keep up," Nichols said.

Despite this important move by Ukraine, Nichols said, "This war isn't even close to over. The only people that can decide when this war is over, the only person that can decide when this war is over, is Vladimir Putin."

Saivetz said it remains unknown what Putin might do next to redress the damage Ukraine caused. She and Nichols said the money and resources the United States has given Ukraine is clearly showing tangible results, and the counteroffensive provides a good case for sending even more money.

Watch: ‘This war isn’t even close to over’: Ukrainian advances spring hope, but not victory