On the same day, German Foreign Minister Frank-Walter Steinmeier said relevant parties should make good use of the planned summit in Minsk to resolve the crisis in Ukraine.
"All parties should know that tomorrow we will once again have a great chance to make a first and important step forward, hopefully to defuse the conflicts and to silence the weapons," he said, adding that relevant parties should "really grab the chance with both hands in the face of impending military conflicts."
Though not a party in the so-called "Normandy Format," U.S. President Barack Obama had phone conversations on Tuesday respectively with Poroshenko and Putin over the matter, according to statements by the White House.
In his phone conversation with Putin, Obama "reiterated America's support for the sovereignty and territorial integrity of Ukraine" and "underscored the importance of President Putin seizing the opportunity presented by the ongoing discussions between Russia, France, Germany and Ukraine to reach a peaceful resolution."
Obama also warned Putin of "rising costs" over what he called Russia's continuing "aggressive actions" in eastern Ukraine, "including by sending troops, weapons and financing to support the separatists," allegations that have been rejected by Moscow.
During his call with Poroshenko, Obama expressed his strong support for the current peace negotiations and both leaders "praised the contributions of Germany and France in the effort to achieve a sustainable, peaceful resolution to the conflict," a White House statement said.
As conflicts in Eastern Ukraine continue to intensify, the Obama administration was re-considering arming Kiev with lethal weapons, but U.S.allies in Europe feared that providing Kiev with such weapons is not an option on the table and believed the move would further escalate the crisis.
During his joint press conference with visiting German Chancellor Angela Merkel on Monday, however, Obama said that it had not been decided yet whether Washington would provide the Ukrainian government troops with lethal weapons.