By Elizabeth Piper and Natalia Zinets
KIEV (Reuters) - President Petro Poroshenko ordered Ukraine's security services and police on Monday to disarm "illegal groups", saying they threatened to further destabilize a country fighting separatists in its east.
Poroshenko said a weekend standoff between members of a far-right group and police in the western town of Mukacheve, close to the border with Hungary, Slovakia and Romania, was simply a turf war over smuggling routes.
But he appeared to take aim at Right Sector, which played a prominent role in protests that toppled Moscow-backed President Viktor Yanukovich last year, saying no political force should operate armed cells in Ukraine and run "criminal cells".
The far-right nationalist group demanded the resignation of the interior minister at the weekend after two of its members were killed in a firefight with police in Mukacheve, where it said it was set upon by police. The Interior Ministry said the group shot first.
Poroshenko said in a statement there needed to be a tough investigation into the events there and that the Interior Ministry, security services and other law enforcement officials must disarm "all illegal armed groups".
"No political force should have and will not have any kind of armed cells. No political organization has the right to establish...criminal groups," Poroshenko said.
Poroshenko said last week the flow of arms from the conflict with pro-Russian separatists in the east increased the risk of serious crime in Ukraine, where corruption flourished under Yanukovich and where the authorities are under fire for not reforming the justice system quickly enough.
The Ukrainian president came one step towards admitting that not enough had been done to combat corruption, saying: "We must get to the bottom of old problems...I'm talking about clans, smuggling, corruption and the like."
The situation was calmer in Mukacheve on Monday but it was not clear whether Right Sector, in turn hailed or blamed for injecting violence into last year's Maidan protests, had downed arms as demanded by the police.
Right Sector has defended its right to hold arms, saying they must protect Ukraine from attempts to derail their demands for a new way of governing and from 'outside forces', mainly Russia, to destabilize the country.
But officials have questioned the need to hold arms in western Ukraine, thousands of kilometers from the east, where fighting has killed more than 6,500 people and forced more than 1.5 million to abandon their homes.
(Writing by Elizabeth Piper, editing by Angus MacSwan)