DONETSK, Ukraine — Just before the most important religious holiday of the year for both Ukrainians and Russians, the Orthodox Easter celebration on Sunday, pro-Russian militant groups have paused what had been the daily expansion of their territory in eastern Ukraine.
They have turned, instead, to consolidating political power over areas already under their control.
In a string of midsize mining and industrial towns that form the core of the area under pro-Russian militant control, centered on the town of Slovyansk, pressure mounted on political dissenters and the media in ways that are commonplace in Russia, but had not been in Ukraine until now.
Internet connections went dead on Saturday in Slovyansk, local news media reported, while Ukrainian television channels blinked off the air, replaced by Russian channels. Pro-Russian militants reportedly accomplished this by seizing a broadcasting tower.
Also in Slovyansk, local newspapers were not distributed after it became clear that at least some editors and reporters did not support the Russian-backed takeover of the town and intended to write critically about it.
The occupiers of government buildings in nearly a dozen cities in eastern Ukraine were preparing to celebrate Orthodox Easter at barricades outside the seized buildings, despite an international agreement for them to vacate the premises and turn in their weapons.
In Donetsk, Denis Pushilin, a cochairman of the self-appointed Donetsk People’s Republic, which is demanding broader regional powers and closer ties to Russia, vowed that insurgents will continue occupying government offices until the new pro-Western Kiev government is dismissed.
‘‘We will leave only after the Kiev junta leaves,’’ Pushilin told the Associated Press outside the occupied regional administration building. ‘‘First Kiev, then Donetsk.’’
At the same time, Pushilin told Russia’s RIA-Novosti news agency that his group could take part in a nationwide roundtable on easing the crisis, which has been proposed by Yulia Tymoshenko, a former prime minister and candidate in the May 25 presidential election.
While the militants have vowed to ignore a diplomatic agreement reached in Geneva on Thursday by the United States, Russia, the European Union, and Ukraine, they halted the expansion of their territory last week.
That had given officials in Kiev some hope that a settlement was still possible, but the tightening of the separatists’ political grip appears to be a setback.
The insurgents say the Kiev authorities, who took power after pro-Russia Ukrainian President Viktor Yanukovych was ousted in February, aim to suppress the country’s Russian-speakers.
The new government, which insists it is legitimate, says it is working on constitutional reforms that will give eastern regions a greater voice in governance.
In another sign of pro-Russian forces’ consolidating politically, they announced Friday that Slovyansk’s elected mayor, who had waffled in her support of their armed seizure of the town and had then mysteriously disappeared, was in their hands and had not been seen in public because she was recovering from a medical operation.
The militants who a week ago overran Slovyansk’s City Hall first said the mayor, Neli Shtyopa, would continue in her position, but work in a separate building.
On Thursday, however, journalists who checked the new building, a dance hall, found it eerily empty except for a woman in a cloakroom, who said nobody had shown up to reestablish the old City Council. Soon enough, all pretense of allowing the elected local government to continue functioning vanished and then so did the mayor.
“She is with us,” Vyachislav Ponomaryov, who has declared himself the new mayor, the “People’s Mayor,” announced late Friday on a loudspeaker set up in front of City Hall, masked gunmen standing behind him.
“She’s in a normal condition,” Ponomaryov said, according to Donbass, an online news portal covering eastern Ukraine. “It’s just that yesterday she had a small crisis. She is recovering from an operation. She doesn’t feel well. She signed a letter of resignation.”
He said pro-Russian militants were protecting Shtyopa from the central government, as Ukraine’s domestic security service had opened a criminal case against her after she initially issued a statement in support of the armed men.