Russia's Foreign Ministry denounced far-right lawlessness in eastern Ukraine and accused Ukrainian officials of denying Russian citizens access to the country.

The ministry said that lawlessness "now rules in eastern regions of Ukraine as a result of the actions of fighters of the so-called 'Right Sector' with the full connivance" of Ukraine's new authorities.

Right Sector is a grouping of several far-right, Russophobe and anti-semitic nationalist factions.

Its supporters were involved in the demonstrations in the Ukrainian capital Kiev, organising so-called "self-defence" brigades for the protest camp that attacked police and broke into public buildings.

The Kremlin statement complained that Russian citizens trying to enter Ukraine have been turned back at the border by Ukrainian officials.

Ukrainian de facto Foreign Minister Andriy Deshchytsya received the foreign ministers of Belgium, the Netherlands and Luxembourg when they came to show support for the government put into office by the recent coup.

He told them that Ukraine is counting on help from abroad to deal with Russia.

Prime Minister Arseniy Yatsenyuk will be welcomed in Washington tomorrow by President Obama.

The US president maintains that the March 16 vote in Crimea organised by local people to legitimise a transfer to Russia would violate international law.

Russian President Vladimir Putin told German Chancellor Angela Merkel and British PM David Cameron on Sunday that he supports the referendum.

"The steps taken by the legitimate leadership of Crimea are based on the norms of international law," he said.