EU leaders stepped up their negotiating efforts this week because of the violence on their eastern border. Two days of shuttle diplomacy produced a peace deal between the opposition and president.
But the opposition quickly took the upper hand, and Russia slammed the deal as tailored for the West.
On Saturday, protesters took control of the capital and police abandoned posts. The parliament voted to remove the president from power and set new elections for May 25.
The president accused the opposition of a coup and said he wouldn't step down, but his rule appears to be crumbling.
His chief rival, ex-Prime Minister Yulia Tymoshenko, is now free from 2½ years in custody, and is promising to run for president. Tymoshenko is already confidently talking about joining the EU, but that prospect seems a long way off given Ukraine's corrupt economy.
The sharp divide between east and west has fueled fears of a messy breakup of the country. That remains a risk, though all sides are pleading against it.
Isachenkov reported from Moscow.