The site of Ukrainian Ministry of Infrastructure is down after a cyberattack.
The ministry said on Facebook that it had received warnings about cyber threats and is taking steps to improve information security.
The International Airport Odesa is also experiencing difficulties in connection with a hacker attack.
"The information system of the International Airport Odesa sustained a hacker attack, all services of the airport operate in emergency mode. We bring apologize to passengers for a forced increase in the time of service," the press-service of the company said.
In Russia, Interfax agency sustained a serious attack, including its corporate information service and the SPARK-Interfax system.
The Kyiv subway also attacked by a computer virus.
"Metro is working in a normal mode, except for its banking services (payment by contactless card or MasterPass cards)", the company said in a statement.
On 27 June, the computer virus Petya attacked Ukrainian companies, including about 30 banks, and government agencies.