Ukrainian telecommunications company Ukrtelecom is in the process of restoring its services after a “powerful” cyberattack detected Monday wreaked havoc on its operations.

Ukrtelecom, through translated updates posted on its Facebook page, said Tuesday it was operating at 85 percent of the level it had been before the attack. The company offers telephone and internet services in the country and is also active in mobile markets.

Watchdog organization NetBlocks shared data on Twitter on Monday that had Ukrtelecom’s connectivity “collapsing to 13% of pre-war levels.”

“Real-time network data show an ongoing and intensifying nation-scale disruption to service, which is the most severe registered since the invasion by Russia,” the organization noted.

In its translated Facebook posts, Ukrtelecom said its IT and technical specialists “repulsed” the attack.

The potential for increased cyberthreats following Russia’s invasion of Ukraine has been covered closely, with experts warning of larger size and scope to attacks believed to originate from Russia. Telecommunications providers are likely to be popular targets, given the detrimental impact loss of their services can have on many individuals.

The threat extends beyond Ukraine, as U.S. regulators have also warned of increased risks.

“Russia’s ongoing cyberattacks against Ukraine could spillover and damage networks outside of Ukraine—as has happened in the past,” said a Feb. 25 alert from the New York State Department of Financial Services. “Escalating tension between the U.S. and Russia also increases the risk that Russian threat actors will directly attack U.S. critical infrastructure in retaliation for sanctions or other steps taken by the U.S. government.”

Tabletop exercises have become a popular practice for companies looking to test their cyber defenses. The trend is explored as part of Compliance Week’s latest members-only case study, “Ransomware Attack,” published in February.