Ukraine’s parliament and other government and banking websites were hit with another punishing wave of distributed-denial-of-service attacks Wednesday, and cybersecurity researchers said unidentified attackers had also infected hundreds of computers with destructive malware, Associated Press reported.

Some of the infected computers were in neighboring Latvia and Lithuania, the researchers said.

Early Thursday local time in Ukraine, as fears of a Russian invasion heightened, the foreign ministry and council of ministers were unreachable and other sites were slow to load, suggesting the DDoS attacks were continuing, though there was no official confirmation. 

Officials have long expected cyber attacks to precede and accompany any Russian military incursion, and analysts said the activity hewed to Russia’s playbook of wedding cyber operations with real-world aggression.

ESET Research Labs said it detected a previously unseen piece of data-wiping malware Wednesday on “hundreds of machines in the country.” It was not clear how many networks were affected.

“With regards whether the malware was successful in its wiping capability, we assume that this indeed was the case and affected machines were wiped,” said ESET research chief Jean-Ian Boutin. He would not name the targets but said they were “large organizations.” ESET was unable to say who was responsible.

Symantec Threat Intelligence detected three organizations hit by the wiper malware — Ukrainian government contractors in Latvia and Lithuania and a financial institution in Ukraine, said Vikram Thakur, its technical director. Both countries are NATO members.

All three had “close affiliation with the government of Ukraine,” said Thakur, indicating the targeted attacks. He said roughly 50 computers at the financial outfit were impacted, some with data wiped.

Asked about the wiper attack, senior Ukrainian cyber defense official Victor Zhora had no comment.