The Foreign Ministry in Moscow on Wednesday described the new Ukrainian law—which Kiev agreed to pass during recent cease-fire negotiations—as a "step in the right direction."
The comments came as a signal to Ukraine—and the Russia-backed separatists—of Moscow's desire to keep the negotiations on track, despite continued, sporadic violence in eastern Ukraine.
Formalizing control for the rebels over part of Ukraine would give Moscow a tool to rein in Kiev's European ambitions.
Moscow also warned that any Ukrainian attempts to backtrack on the legislation risked reviving the deadly conflict.
"We hope that all provisions of the law will be implemented responsibly," the ministry said.
"It is clear that the attempts of well-known political groups in Ukraine to cancel it or change its essence will renew the confrontation in the southeast and undermine efforts of the international community and sensible politicians in the country to normalize the situation."
Ukrainian President Petro Poroshenko has defended the law, which passed parliament on Tuesday.
His aide responsible for the eastern part of the country said rebel-held areas would gradually return to the control of the central government.
But former Prime Minister Yulia Tymoshenko, a rival to the president, said she would go to court to challenge the new law and another granting amnesty for some participants in the uprising in the Donetsk and Luhansk regions.
"It is still not too late to go back to a pro-Ukrainian, patriotic position and veto these two laws," Ms. Tymoshenko said, calling on the president to change course.
The law grants three years of self-governance to certain areas of the Donetsk and Luhansk regions, with the boundaries to be designated by Ukrainian authorities.
It calls for elections on Dec. 7 in those areas, guarantees the right to use of the Russian language and authorizes local control over economic development.
"It means that for some districts that are under the control of gunmen, the Ukrainian government is giving them a special chance for local self-governance to resolve the problem in a nonmilitary manner," Iryna Herashchenko, an aide to the president, said on Wednesday.
Some of Mr. Poroshenko's allies have criticized what they called vagueness and gaps in the new law.
Serhiy Taruta, the tycoon appointed governor of the Donetsk region by Kiev earlier this year, said it didn't make clear what territories would fall under the special designation, how the border would work or the relationship of those areas with the national government.
"Over what period do people have to lay down their arms? We didn't see this," Mr. Taruta said at a briefing late Tuesday.
"When and how will the border be closed? That is also unclear."
Over the summer, Ukrainian forces were taking territory from pro-Russia separatists in the east and closing in on their strongholds.
But what Western and Ukrainian officials described as a Russian incursion late last month propped up the rebels and sent the Ukrainian military into retreat.
Since then, Kiev has been forced into negotiating a truce.
Demands by Russia and the rebels for Kiev to grant more autonomy to the rebel-held regions—something that some Ukrainian officials warn would cement Moscow's influence over its neighbor—has become a key condition of those talks.
Donetsk rebel official Andrei Purgin expressed satisfaction with parts of the law in an interview with the BBC and vowed to continue negotiations.
In a separate interview with the Interfax news agency, Purgin said the Donetsk rebels were already working on a project to receive direct natural-gas deliveries from Russia into rebel-held territory via a Soviet-era pipeline.
"Technical work is now being carried out," he said.
"So far the question of price hasn't been raised."
Some separatists have continued to demand full independence.
Donetsk rebel leader Alexander Zakharchenko, meanwhile, rejected the idea of holding local elections in cooperation with Ukraine.
"We have our own Supreme Council, and we will be deciding for ourselves how and when to hold elections," Zakharchenko told Interfax.
"No elections organized by Ukraine are going to be held here."
Meanwhile, fighting has continued in the conflict zone between pro-Russia rebels and Ukrainian forces despite the cease-fire.
A rebel attack near the town of Nyzhnya Krynka in the Donetsk region destroyed nine residential buildings on Wednesday and killed more than 10 civilians, the Ukrainian military said.
On Sunday, monitors from the Organization for Security and Cooperation in Europe came under fire in a nearby area.
Russia's envoy to the OSCE accused the Ukrainian armed forces of continuing to shell residential areas in violation of the cease-fire agreement.
Still, he said the pact remained in place.
"I wouldn't say it is a catastrophe," Andrei Kelin told Interfax.
"The OSCE doesn't regard it as a termination of the cease-fire, but the danger is there."
Source: The Wall Street Journal