• Stian Jenssen, director of the private office of the NATO secretary-general, was criticized over comments during a panel debate Tuesday.
• Jenssen subsequently told Norwegian newspaper VG that his choice of words was a mistake.

NATO official Stian Jenssen on Wednesday said comments he made the previous day regarding Ukraine ceding land in order to gain membership in the military alliance were a "mistake."

Jenssen said during a panel debate in Arendal, Norway, "I think that a solution could be for Ukraine to give up territory, and get NATO membership in return," Norwegian newspaper VG reported Tuesday. He also said it was up to Ukraine to decide when and on what terms it negotiates.

He told VG in a follow-up interview Wednesday, "My statement about this was part of a larger discussion about possible future scenarios in Ukraine, and I shouldn't have said it that way. It was a mistake."

A NATO press officer directed CNBC to the new VG article when asked for a statement from Jenssen, who is director of the private office of NATO Secretary-General Jens Stoltenberg.

The initial comment caused a stir in Kyiv. His words appeared to be criticized by Ukrainian presidential advisor Mykhailo Podolyak on social media, who called the concept of giving up territory for NATO membership "ridiculous."

Podolyak added that to do so would be "deliberately choosing the defeat of democracy, encouraging a global criminal, preserving the Russian regime, destroying international law, and passing the war on to other generations."

Ukrainian President Volodymyr Zelenskyy and other officials have repeatedly said Ukraine is not willing to give up any of its territory in order to reach a peace deal to end the war with Russia.

In the follow-up interview Wednesday, Jenssen said he had always stressed any decision was entirely Ukraine's to make.

He also said the most important thing was to continue to support Ukraine with its counteroffensive.

"Many have commented that it is going a little slower than they had hoped. I would still like to add a seed of optimism to this, as I also said in the Arendal debate. One must remember that at the outbreak of war there was a concern that Ukraine could collapse within weeks and days," he told VG.

"It has not happened at all. They have shown a heroic effort against the superior power. The topic now is how much territory Ukraine is able to take back," he said.

Kyiv applied for fast-track NATO membership in September 2022. NATO allies in 2023 stated a commitment to eventual Ukraine membership under certain conditions, including "democratic and security sector reforms."