Russian President Vladimir Putin is in Cairo for talks with Egyptian President Abdel-Fattah el-Sisi, one day before a critical meeting in Minsk over the future of Ukraine.
The president said the option was one of many he was considering if diplomacy fails. Germany's chancellor, who held a joint news conference with the president, backs diplomacy to end the crisis.
Buses were allowed to carry people out of harm's way during a stay of hostilities, which have displaced some 1.6 million. Talks between Ukraine, Russia, Germany and France are to continue Sunday.
Gen. Philip Breedlove, NATO's supreme allied commander of Europe, tells NPR that "hundreds and hundreds" of Russian troops as assisting separatists in eastern Ukraine.
At least eight civilians have been killed in the past 24 hours and 22 wounded in fighting between pro-Russian rebels and Ukrainian troops in the separatist stronghold of Donetsk.
The eastern Ukrainian city of Donetsk has been under siege and subject to artillery and rocket attacks for months — residents are living in stressful conditions and the separatist militia is jumpy.
Russia is jailing three prominent figures from Ukraine and Estonia on what critics say are highly questionable charges. The cases also reflect the friction between Russia and its neighbors.
Igor Girkin claims to have touched off the conflagration, and he says he's proud of what he did. The former member of the Russian security service has a knack for turning up in tumultuous places.
The Russian economy took a big hit in 2014. The U.S. and other countries imposed economic sanctions after Russia annexed Crimea, but it was falling oil prices that really hurt the country.