Ukraine violence

President Barack Obama on Saturday called on Russian President Vladimir Putin to de-escalate the tense atmosphere in Ukraine by pulling his forces back to bases in the country's Crimean region and to refrain from interfering elsewhere in the former Soviet republic.

Ukraine's presidency said Friday that it has negotiated an international deal intended to end battles between police and protesters that have killed scores and injured hundreds. It was unclear whether the deal would appease protesters, and shots rang out Friday morning in central Kiev.

Fearing that a call for a truce was a ruse, protesters tossed firebombs and advanced upon police lines Thursday in Ukraine's embattled capital. Government snipers shot back and the almost-medieval melee that ensued left at least 70 people dead and hundreds injured.

Fierce clashes between police and protesters in Ukraine's capital have erupted anew Thursday and an Associated Press reporter has seen 10 bodies laid out on the edge of the protest encampment.

Sergei Bubka, the pole vault great who heads the Ukrainian Olympic Committee, urged both sides Wednesday in Ukraine's political crisis to lay down their weapons and halt the violence that is bringing the country to "the brink of catastrophe."