Ukraine's foreign minister has accused Russian troops of infiltrating and destabilising the east of the country, saying Moscow plans to invade and annex other regions.
In an interview with Al Jazeera, Andrii Deshchytsia said that Russian "special troops" and intelligence officers were blackmailing and intimidating Ukrainian citizens to create a false impression of popular support for Moscow.
The comments came as his Russian counterpart, Sergey Lavrov, suggested both sides hold talks under the aegis of the Organisation for Security and Cooperation in Europe.
"Russia believes that such a dialogue could be arranged between the authorities in Kiev and their opponents in other regions," Lavrov told Rossiya-24 TV.
OSCE military monitors are in eastern Ukraine following an agreement struck in Geneva between the US, the EU, Russia and Ukraine to ease tensions. However, staff have been blocked and harassed, with one group being arrested by pro-Russian separatists.
Deshchytsia said: "Special troops from the Russian army and intelligence have infiltrated eastern Ukraine. These well-equipped groups resort to guns, oppression and blackmail to intimidate people ... in an effort to channel them to their own purposes, and thus create the false impression that their demands are backed by broad public support."
He said that the Geneva agreement "remained on paper" as Russia had done nothing to implement its terms.
"Ukraine took certain steps in this regard such as gearing down anti-terrorism operations, drafting an amnesty law, ensuring evacuation of government buildings and streets seized by various groups, embarking on a constitutional reform for local administrative bodies, and making things easier for the OSCE mission."
"Russia's major goal is to destabilise and control the country. We will not let this happen. Russia wants to hamper the presidential elections in May and also to make the legitimacy of the new government disputable.
"They want to destabilise Ukraine. If they cannot achieve that, they will want to invade and annex certain parts of Ukraine through a direct military intervention."
He said he understood the West would not enter an armed conflict with Russia, but that it could do more to stop the Russian machine working.
"Western countries should implement tougher sanctions which should target certain Russian sectors. Oil and natural gas revenues allow Russia to arm its military forces and invade territory," he said, adding that sanctions should be brought against "decision-makers", including the Russian president, Vladimir Putin.
The International Monetary Fund on Wednesday announced a $17bn bailout for Ukraine, while also announcing that Russia was entering into a recession.
Deniz Berktay interviewed Andrii Deshchytsia for Al Jazeera Turk.