Russia hasn’t demonstrated very sophisticated or destructive cyberattacks and Ukraine is able to resist attempts to hack its infrastructure, according to a top Ukrainian cyber official.

“Russian cyber offensive operations likely reached their full potential and we do believe the international community will be able to keep them at bay,” said Victor Zhora, deputy chief of Ukraine’s State Service of Special Communication and Information Protection, speaking with reporters on Wednesday.

“They did not offer anything special during these two months,” he said, referring to Russian hackers. Sophisticated cyberattacks take months to plan and Russia can’t “scale their cyber warriors,” he added.

The number of attempted cyberattacks and scanning of Ukrainian critical infrastructure, a step hackers take to identify security flaws, has increased threefold since the start of the war, compared with the same period in 2021, Mr. Zhora said. Russian hackers have been attempting to hack the telecoms and energy sector and could continue to keep targeting those industries, he added.

“We shouldn’t underestimate Russian hackers, but we probably should not overestimate their potential since their potential isn’t growing now,” he said.

Countries need to cooperate to defend against Russian cybersecurity actions, Mr. Zhora said. One way to curb Russia’s cyber capabilities is through sanctions limiting the technology available there, he said.

Information-technology spending in Russia is expected to drop 39% this year, according to researcher International Data Corp., as global business sanctions triggered by the invasion of Ukraine take their toll. Tech giants including Microsoft Corp. , Amazon.com Inc.’s Amazon Web Services and Alphabet Inc.’s Google Cloud have said they are suspending new sales or the acceptance of new customers in Russia.

Ukrainian officials said this month that they had stopped a cyberattack on an electricity company that used code similar to malware known as Industroyer, which was used in a December 2016 attack on Ukraine’s power grid. Ukrainian officials said the Sandworm hacker group was behind the attack. The U.S. has linked Sandworm to the Russian military, which Russia has consistently denied.