Russia is going to have a tough time trying to take Kursk back from Ukraine, says CIA deputy director

• David Cohen says the Russians are in for a "difficult fight" if they want to take back Kursk.
• Ukraine caught the Russians off guard when it launched a shock offensive into Kursk on August 6.
• Besides losing territory, Cohen said Putin now has to deal with Ukrainian forces within Russia.

Reclaiming Kursk from the Ukrainians is going to be a "difficult fight" for the Russians, says CIA deputy director David Cohen.

Cohen was speaking at the Intelligence and National Security Summit in Washington on Wednesday when he weighed in on Ukraine's shock offensive into the Kursk region.

The surprise attack on August 6 caught the Russians off guard and allowed the Ukrainians to notch significant gains on the battlefield.

The commander in chief of Ukraine's military, Oleksandr Syrskyi, said on August 12 that they'd seized nearly 400 square miles of Russian territory in just a few days. That's as much territory Russia has seized from Ukraine in this year.

"We can be certain that Putin will mount a counteroffensive to try to reclaim that territory," Cohen said on Wednesday, per Reuters .

"I think our expectation is that that will be a difficult fight for the Russians," he added.

The shock offensive poses multiple challenges to Russian leader Vladimir Putin, said Cohen, who not only has to deal with a "front line now within Russian territory" but also the "reverberations back in his own society that they have lost a piece of Russian territory."

To be sure, Russia has already begun mobilizing its troops to take back Kursk.

Last week, a Ukrainian commander with the call sign Cold told The Wall Street Journal that Russia is sending in better-equipped soldiers to the region.

This is in contrast to the Kursk incursion's early days, which saw Russian soldiers surrendering en masse to invading Ukrainians.

Cohen also acknowledged the gains Russians had made in Ukraine's eastern Donetsk region , but noted that this came at an "extraordinary cost" in terms of the resources being expended.

"But at the end of the day, none of it is a game changer in a strategic sense," Cohen said on Wednesday.

Russia's defense ministry didn't immediately respond to a request for comment from Business Insider sent outside regular business hours.