The president said that 700 Ukrainian prisoners had been released, with another 500 in custody. Most of those would appear to be soldiers, because a government spokesman said Wednesday that only 20 soldiers had been released so far.

Mr. Poroshenko gave no specifics about the bill on special status for the areas held by the rebels. The agreement reached in Minsk last Friday calls for Ukraine to move toward “decentralization,” first by adopting a temporary law that gives special status to certain districts of the Donetsk and Luhansk regions.

Officials and analysts noted that important questions remain about that provision. Officials at the Foreign Ministry in Kiev declined to comment on Ukraine’s negotiating position.

But a political adviser to Mr. Poroshenko said that each of the 12 points in the cease-fire protocol needed to be negotiated in detail, with the government focused first on silencing the guns and obtaining the release of hundreds of prisoners.

“Nobody knows what special status means,” said the adviser, speaking on the condition of anonymity because he was not directly involved in the talks. He said Ukraine rejected the idea of federalization, particularly since the area held by the rebels represented only about one-third of the territory of the two regions.

Russia has been pushing since March for federalization, seen as a means to give the regions sufficient autonomy so that they could veto any national legislation that might move Ukraine closer to the West, particularly joining NATO. Regardless of whether Russia accomplishes that goal, there has been concern that Russia’s president, Vladimir V. Putin, might try to create a frozen conflict in the area, leaving Ukraine permanently destabilized.

Mr. Putin has had little to say about Ukraine since the cease-fire was signed. He said in Moscow on Wednesday that Russia would continue to build up its military with large-scale weapons purchases to meet any threat, particularly from the United States and NATO.