Fighting broke out in eastern Ukraine on Wednesday as pro-Russian insurgents from Sloviansk attacked government forces surrounding the rebel-held city.
A rebel representative in Sloviansk told the Russian Interfax news agency that the fighting was concentrated around a television tower in the southern suburb of Andreyevka. “We are taking the checkpoints back under our control,” he said.
There was no immediate information on casualties, nor did the Ukrainian government comment on the reports.
Interior Minister Arsen Avakov, who has been coordinating the operation in the region, said on Monday that the television tower had been retaken and was broadcasting Ukrainian channels.
Separatists, many of them heavily armed, have seized more strategic sites in the Donetsk and Luhansk regions in the past weeks, prompting the Ukrainian government to admit that it has lost control there.
Mr. Avakov claimed that government forces had retaken control of the city of Mariupol. “Mariupol has been completely freed” he said in a statement on his Ministry’s website.
Unconfirmed reports said that at least one pro-Russian activist was killed during the nightly raid on the city administration building.
Hundreds of pro-Russian activists gathered outside the administration building to protest against the eviction, 0629.com.ua news site reported.
An industrial city of almost half a million that borders the Sea of Azov, Mariupol is the second-largest city in the Donetsk region.
Later on Wednesday, Swiss President and Foreign Minister Didier Burkhalter was to hold talks with Russian President Vladimir Putin on the crisis.
Mr. Burkhalter, who chairs the Organisation for Security and Cooperation (OSCE), is expected to advocate better implementation of the Geneva de-escalation agreement reached last month between Ukraine, Russia, the United States and the European Union, diplomats said.
Russia has blamed the West and Ukraine for not implementing the agreement, which stipulates the disarmament of all illegal groups and the vacating of occupied buildings throughout Ukraine.
Mr. Bukrkalter on Wednesday advocated an action plan, under which the four parties would back the May 25 presidential elections in Ukraine and a parallel referendum on decentralization.
However, the Ukrainian Parliament, in a vote on Tuesday, rejected a plan for holding a referendum with the elections.
Plans by the insurgents to hold a referendum on the regions’ future status on Sunday were condemned by the United States and the European Union on Tuesday.
E.U. president Herman Van Rompuy said the bloc was drawing up plans to help Ukraine reform its security sector.
“The E.U. is ready to assist Ukraine in the field of civilian security sector reforms,” Mr. Van Rompuy said, after talks in Brussels with Japanese Prime Minister Shinzo Abe.
E.U. Foreign Ministers are expected to make a decision on such proposals when they meet on Monday, Mr. Van Rompuy added.
Mr. Abe, meanwhile, said that Japan would send 10 observers to help oversee a presidential election in Ukraine scheduled for May 25.
Russia has said the election should not be held while the government’s military operation in the east continues.
The separatists in the east plan to hold a referendum at the weekend on secession from Ukraine.
Presidential candidate Petr Poroshenko, regarded as a lead contender in the May election, urged the West to impose new sanctions on Russia in the separatists go ahead with the referendum.
“Should Russia support this referendum, we absolutely need a concerted response in the form of a third wave of sanctions,” Mr. Poroshenko said in Berlin, where he will meet German Chancellor Angela Merkel and Foreign Minister Frank-Walter Steinmeier.
Meanwhile, the International Monetary Fund (IMF) paid a first tranche of aid loans approved for Ukraine to avoid bankruptcy.
The Ukrainian National Bank said that it received a $3.19 billion payment from the IMF, local media reported.
The IMF has promised $17 billion in aid to Kiev.
