The group of nations accused the Russian government of flouting agreements made in Geneva and said the already significant “costs” for President Vladimir Putin would increase.Pro-Russian militias are still occupying buildings in more than 10 cities in the east of the country and the nationalist Right Sector movement is in control of two public buildings in Kiev.Negotiators are also trying to secure the release of international observers seized by pro-Russia gunmen and accused of espionage in Sloviansk.In a statement, David Cameron, Barack Obama and counterparts from Germany, France, Italy, Japan, and Canada expressed "deep concern at the continued efforts by separatists backed by Russia to destabilise eastern Ukraine".It claimed that Moscow had taken "no concrete actions in support of the Geneva accord" and had not condemned pro-Russia militants or urged them to leave buildings they have been occupying.The statement added: "We reiterate our strong condemnation of Russia's illegal attempt to annex Crimea and Sevastopol, which we do not recognise."We will now follow through on the full legal and practical consequences of this illegal annexation, including but not limited to the economic, trade and financial areas."We have now agreed that we will move swiftly to impose additional sanctions on Russia."Given the urgency of securing the opportunity for a successful and peaceful democratic vote next month in Ukraine's presidential elections, we have committed to act urgently to intensify targeted sanctions and measures to increase the costs of Russia's actions."No details of the sanctions have been given but the measures are expected to be announced next week.The move follows an intense round of diplomacy on Friday, including a conference call between President Obama and European leaders.The agreement struck between Moscow and Ukraine in Geneva last week was hailed as a breakthrough, and called for all parties to down arms and vacate public buildings.Public exchanges between the sides have become increasingly bitter, with the Russia's Foreign Minister, Sergey Lavrov, accusing the West of plotting to control Ukraine.He said pro-Moscow insurgents in the south east of the country would lay down their arms only if the Ukrainian government cleared the Maidan protest camp in the capital, where the pro-European protests that led to the ousting of Viktor Yanukovych started last year."The West wants - and this is how it all began - to seize control of Ukraine because of their own political ambitions, not in the interests of the Ukrainian people," Mr Lavrov said.But John Kerry, the US Secretary of State, said the Russian government had “refused to take a single concrete step in the right direction”.He added: "Not a single Russian official, not one, has publicly gone on television in Ukraine and called on the separatists to support the Geneva agreement, to support the stand-down, to give up their weapons, and get out of the Ukrainian buildings."Arseniy Yatsenyuk, the Prime Minister of Ukraine, has accused Russia of wanting to start "a third world war" and there have are reports that Russian jets have been violating Ukrainian airspace.Speaking in Rome on Saturday, Mr Yatsenuk said: "Russian military aircraft today at night crossed and violated Ukrainian airspace seven times. The only reason is to provoke Ukraine... and to accuse Ukraine of waging war against Russia."(independent.co.uk)ANN.Az