Ukrainian President Volodymyr Zelensky gave a basically upbeat assessment of Ukraine’s long-awaited “counteroffensive” against invading Russian forces but conceded “nobody knows” if there will be a major breakthrough this year in an interview with CNN on Tuesday.

Zelensky added that he thinks “we will have more success” in the coming year, following a slower-than-expected start for the big counteroffensive. As in several other recent interviews, he disputed criticism that Ukraine’s push has deteriorated into a stalemate, pointing to gains made by his forces in the east of the country.

Ukraine’s timetable to begin producing strategically significant results might not be as long as Zelensky would like. Two weeks ago, U.S. Chairman of the Joint Chiefs of Staff Gen. Mark Milley warned there are only “about 30 to 45 days left” of decent weather for military operations this year.

“I said at the very beginning of this that this was going to be long, slow, hard, and high-casualty-producing, and that’s exactly what it is,” Milley said.

Zelensky told CNN on Tuesday that more advanced weapons, such as American long-range missiles and Patriot air defense systems, would be crucial to breaking Russia’s defenses. Without those weapons, he predicted “more casualties on the battlefield and elsewhere.”

“We are on the finishing line. I’m sure of that,” he said.

Asked about growing skepticism in Washington for continued heavy funding of the Ukrainian war effort when it seems unable to make significant gains against the Russians, Zelensky said it was “difficult” for outsiders to understand the realities of the battlefield.

Zelensky also defended Ukraine’s missile strikes on Russian positions in Crimea, which have been criticized by some U.S. officials as a waste of resources that risks damage to civilians with little strategic payoff.

“Temporary-occupied Crimea – it’s a place they store weapons to kill our civilians. They’re shooting from Crimea into our territory. And of course, we have to see where their rockets are coming from, and we have to basically deal with it,” he said.

The far-left New York Times on Thursday noted that “polls have detected a growing weariness over the war among the American public, which is focused on problems at home.” Republican leaders like House Speaker Kevin McCarthy (R-CA) are looking for more “accountability” on funds sent to Ukraine, it continued, and even some quarters of the Biden administration are growing uneasy about escalating requests from Kyiv for more powerful weapons.

One of those polls came from CNN, which found in August that 55 percent of the American public believes “Congress should not authorize additional funding to support Ukraine.” Fifty-one percent said the U.S. has already done enough to help Ukraine repel the Russian invasion, a slide of 11 percent from public support for assisting Ukraine in the early days of the war.

White House spokesman John Kirby on Wednesday admitted Ukraine’s progress on the battlefield is “not as far or as fast as they themselves have said they’d like to go.” Kirby was nevertheless confident that Congress would vote in favor of continued support.