Oren Dorell

USA TODAY

The cease-fire agreement between Ukraine and Russian-backed separatists who hold territory in eastern Ukraine marks a clear victory for Russian President Vladimir Putin. It weakens the Kiev government's control over the region and blocks Ukraine's hopes of economic and military union with the West.

By backing a rebel counteroffensive that forced Kiev to seek a truce, Putin appears to be achieving a goal he previously reached in other former Soviet republics: establishing autonomous, pro-Russian regions that frustrate efforts by those countries to join the European Union and NATO — steps Putin views as threats to his homeland.

"It's very possible the cease-fire could be a first step toward a frozen conflict," says Ian Brzezinski, a former Defense Department official who worked on Europe and NATO policy under President George W. Bush. "To date, we don't have much confidence that Putin won't exploit this to consolidate the gains he's made in eastern Ukraine."

A frozen conflict occurs when an outside or insurgent force seizes a country's territory and holds it indefinitely, Brzezinski said.

"For Ukraine, it means territory is occupied and it has to maintain its military at a high state of readiness," he said. "A significant chunk of territory cannot be integrated into the Ukraine economy. It represents a real setback for its integration into Europe because it's going to be an economic burden."

An ongoing territorial dispute will impede Ukraine's moves to join European institutions, whose members "don't want to inherit those conflicts," Brzezinski said.

Russia has employed similar tactics when the former Soviet republics of Moldova and Georgia sought closer relations with EU and NATO membership. Russian "peacekeepers" continue to occupy Moldova's Transnistria region and Georgia's South Ossetia and Abkhazia regions to protect ethnic Russian separatists living there. A significant percentage of residents in east Ukraine also are ethnic Russians, many of whom favor autonomy from the central government in Kiev.

Ukraine President Petro Poroshenko said he and Putin spoke by phone Saturday and agreed that the fragile cease-fire appeared to be holding.

Putin forced Ukraine into a cease-fire by pouring in help for the rebels to help them reverse a series of defeats and regain ground as Ukrainian troops appeared to be on the verge of crushing the rebellion. Putin continues to deny providing military support, but NATO and Ukraine say the evidence is indisputable.

In negotiating the cease-fire, Putin "has made it absolutely clear that in this part of the world, a U.S. or NATO presence will not be accepted and the ground rules will be determined by Russia," said Toby Gati, who helped shape U.S. policy toward Russia for President Clinton. "This is not an issue he will allow Ukraine to decide for itself or allow Ukraine to decide with the West."

The text of the cease-fire agreement signed Friday has yet to be released. Poroshenko said it allows Ukraine to assert sovereignty over its territory, while providing increased autonomy to rebel-held areas.

Reports from those areas indicate that asserting Ukrainian sovereignty may be difficult. In a series of comments posted on Twitter, German politician Marieluise Beck, who visited the separatist-held city of Luhansk, described it as "full of Russian soldiers" who were building structures and "going from house to house in Lugansk, giving out food parcels and 1,000 rubles for each adult and 500 for children," according to a translation in the online journal The Interpreter.

Separatist leader Igor Strelkov continues to raise money on his website. On Saturday, he posted photographs of a new batch of weapons, body armor and other military equipment his men recently procured.

Andrew Weiss, a Russia and Ukraine analyst at the Carnegie Endowment for International Peace, questions whether paramilitary combatants on either side in eastern Ukraine will observe the truce.

"The real danger" he said, "is these groups will see this agreement as a sell out and will not abide by it."