Interim President Oleksander Turchinov asked the Justice Ministry on Monday to ban the Communist Party for its role in activities that threaten Ukraine's security and territorial integrity.
"I am asking the Ministry of Justice to immediately take the measures established by the law to ban the Communist Party of Ukraine," Turchinov said in a letter to Justice Minister Pavel Petrenko.
Turchinov accused the Communist Party of "participating in activities aimed at violating the sovereignty and territorial integrity, threatening its security and illegally taking power" in Ukraine.
The communists' policies "have an openly anti-constitutional character," the acting president said.
Communist Party members in southern and eastern Ukraine "not only support the terrorists, but they offer practical, material and technical assistance to the representatives of the so-called people's republics of Donetsk and Lugansk," Turchinov said.
Voters in Lugansk and Donetsk cast ballots in independence referendums on May 11.
Some 96 percent of voters in Lugansk cast ballots in favor of independence, while 89 percent of voters in the neighboring region of Donetsk backed breaking away from Ukraine.
Donetsk has been at the center of the pro-Russian uprising against the central government that started in early April.
Pro-Russian separatist leaders in both regions said they planned to create government agencies and military forces, aiming for independent states in the near future as they follow the path taken by Odessa and other regions.
Ukraine's government leaders contend that the referendums were not valid.
Long-simmering tensions between pro-European western Ukraine and the country's eastern region, which has close ties with Russia, were exacerbated by the ouster in late February of President Viktor Yanukovych, a Russian-speaker from the East.
The crisis that led to Yanukovych's ouster erupted at the end of November, when Yanukovych backed away from plans to ink a pact with the European Union and instead signed a $15 billion financial aid package with Russia.
Brussels's offer of closer ties with the EU was conditioned on a pledge by Ukraine not to enter into any additional economic accords with Russia, Kiev's leading trade partner and energy supplier. EFE