Arseniy Yatsenyuk told a conference attended by Ukrainian and European lawmakers and business leaders in Kyiv on Saturday that he was convinced that Putin's goal was "not just to take Donetsk and Luhansk."
"His goal is to take the entire Ukraine... he wants to eliminate Ukraine as an independent country," Yatsenyuk said.
The Ukrainian prime minister described a ceasefire signed by his government, the Organization for Security and cooperation in Europe, pro-Russia separatists and Russia in Minsk earlier this month as just a "first step."
He also called on the European Union and the United States to play a direct role in talks towards a peace agreement that would ensure Ukraine's long-term sovereignty.
"They (Moscow) will outplay us," Yatsenyuk warned. "Putin wants to get another frozen conflict and get his hands on our belly fat."
Second Russian convoy
Meanwhile, Russian media reported late on Friday that another Russian aid convoy had crossed the border into eastern Ukaine.
"Russian customs officers and border guards completed processing the first group of trucks... Now all 35 trucks have left the border crossing point towards Ukraine," Rayan Farukshin, a spokesman for the southern customs office, told the RIA Novosti news agency.
The agency reported that the convoy was carrying canned food, sugar, flour and diesel generators.
However the total number of vehicles in the convoy was not immediately clear, with some reports putting the figure as high as 300.
A previous Russian convoy of more than 200 trucks rolled across the border in late August without the approval of the Ukrainian authorities - a move Kyiv described as "a direct invasion."
pfd/shs (AFP, Reuters, AP)