The US official said that Putin would not be able to take all of the country.
Colin Kahl is the Under Secretary of Defense for Policy.
The Ukrainians are fighting against Russia's invasion.
A top Pentagon official said that Putin probably won't be able to capture the entire eastern European country.
The Under Secretary of Defense for Policy believes that he has designs on a significant portion of the country.
While speaking at the Center for a New American Security's National Security Conference, Kahl stated that he did not think he could achieve those objectives.
The US official said that Russian forces may make gains, but that the Ukrainians are holding their ground.
"I don't believe the Russians have the ability to achieve those grandiose objectives," he said.
The capital city of Kyiv was not captured early on in the war.
The Russians were badly defeated in the battle of Kyiv and he thinks he imagined a thunder run to the city. They were pushed out of the city.
The Russians have made gains in the south and east of the country, but the Ukrainians have remained steadfast.
According to the UK's Ministry of Defense, it is highly unlikely that Russia anticipated such robust opposition or such slow, attritional conflict.
Since the war began in February, thousands have been killed on both sides of the conflict.
Ukrainian President Volodymyr Zelenskyy and the West have accused Putin's forces of committing heinous war crimes.
Business Insider has an article on it.