( CNN ) -- Ukrainian President Petro Poroshenko said early Tuesday that his country will not renew a cease-fire with pro-Russian separatists , vowing instead `` we will advance , and we will liberate our land . '' The fragile cease-fire expired at midnight Monday -- hours after Poroshenko spoke by phone with Russian President Vladimir Putin , German Chancellor Angela Merkel and French President Francois Hollande . The cease-fire -- agreed upon earlier this month amid a volatile political crisis -- raised hopes that Ukraine could be moving back from the brink of full-fledged civil war . The crisis has its roots in former President Viktor Yanukovych 's decision to shun a European Union Association Agreement last year and work with Russia instead . The move unleashed deadly strife that led to Yanukovych 's ouster , Ukraine 's loss of Crimea and a pro-Russia separatist rebellion . Russia and Ukraine have been engaged in a tense standoff since the Russian annexation of Crimea in March , when Russia also massed troops along its western border with Ukraine . After Monday 's phone call , Poroshenko said his goal was peace , but said it takes the participation of all parties to maintain stability , noting violations of the cease-fire by pro-Russian separatists . A statement from Putin 's press office about the call said the Russian President `` stressed the need to extend the cease-fire and also establish a reliable mechanism for monitoring '' it .
The cease-fire expired at midnight Monday . Poroshenko spoke earlier in the day with Russia 's Putin and intermediaries . In a statement released by his office, he said that Ukraine was ready to resume talks on "practical measures" for de-escalation of tensions between Kiev and pro-Russian separatists, but did not specify what those