DONETSK, Ukraine (CNN) — Ukrainian security forces launched an operation on Sunday to clear pro-Russian separatists from a police headquarters in the eastern city of Slaviansk, officials said, with Kiev reporting one dead.
However a CNN crew in the city saw no sign of a large presence of Ukrainian security forces nor any confrontation with the occupiers.
Gunmen dressed in camouflage had stormed and seized the police building a day earlier in Slaviansk, a town about 100 miles from the Russian border, and set up barricades around it.
In a post on his Facebook account Sunday morning, Interior Minister Arsen Avakov said an “anti-terrorist operation” had started in Slaviansk.
“It is managed by Anti-terrorist Center of the Security Service of Ukraine. All the law enforcement agencies of the country are participating. Godspeed!” Avakov wrote.
“Tell all civilians to leave the center of town — don’t leave your apartment, or go to the window,” he added.
He later commented on his own Facebook post, saying that a state security officer had been killed.
Kiev’s Foreign Ministry said in a statement that authorities had “decided to launch a full-scale anti-terrorist operation against those who attempt to destroy our country.”
Giving no further details, it also said it had “concrete evidence of Russian special service involvement” in the pro-Russian protests and storming of buildings in the east in recent days and would present it at an international meeting on the Ukraine crisis on Thursday. There was no immediate response from Moscow.
On a tour of the town, the CNN crew saw no mass security presence — with the exception of a single police car and a helicopter flying above.
Kiev’s fragile new government and the West accuse Russia of destabilizing the region as a pretext to potentially send in troops to protect the local Russian-speaking population.
NATO says Russian armed forces are massing on Ukraine’s eastern border, while Moscow says they are merely carrying out military exercises.
Russian and local Ukrainian media reported that pro-Russian demonstrators had seized the city hall in Mariupol, in the southeast, with no violence. Some showed pictures of Russian flags in the city. The reports could not immediately be independently confirmed.
In Slaviansk, the gunmen had arrived at the police station in two minibuses on Saturday. They opened fire at the police station before entering it through windows, Donetsk regional police said. Three police officers were slightly injured.
The gunmen introduced themselves as part of the Donetsk Republic initiative group. Their goal was to seize hundreds of weapons inside the police building; they allowed the police officers inside to leave the facility, the press office said.
A CNN team in Slaviansk had seen dozens of armed, well-equipped men in camouflage in control of the Ukraine Security Services building, as well as the police building. The men did not want to be filmed.
Makeshift barricades have been erected around both buildings and local residents brought food and tires to the armed men at the security services site.
The unrest is the latest show of spiraling anger in eastern Ukraine, which has a large Russian-speaking population. The region was the support base for pro-Moscow former President Viktor Yanukovych, who was ousted in February following months of protests in the capital, Kiev.
Distrust among the population in the region grew as political power in the national government shifted rapidly in a pro-Western direction. A short time later, pro-Russian elements occupied the Black Sea peninsula of Crimea, which Russia quickly annexed. Since then, pro-Russian protesters have taken to the streets in eastern Ukrainian regions and in some cases stormed and occupied buildings.
“We want to create a people’s republic, a real one, one in Donetsk, one in Luhansk, and in general, let the people of the southeast determine what they want. We want to hold a referendum,” one pro-Russian armed activist in Slaviansk told Reuters.
In Kramatorsk, also in the east, police and pro-Russia activists exchanged gunfire on Saturday, Avakov’s spokeswoman Natalia Stativko said.
In the cities of Donetsk, Luhansk and Kharkiv, pro-Russian protesters seized government buildings several days ago and remain barricaded in some.
The Donetsk chief of regional police, Kostyantyn Pozhydayev, announced his resignation during a pro-Russia activist rally outside the police office Saturday, according to a police press statement. The head of the Security Service for the region, Valery Ivanov, was sacked, authorities said.
The United States has accused Russia of fomenting the separatist unrest in its neighbor as a pretext for military intervention.
U.S. Secretary of State John Kerry spoke by phone with Russian Foreign Minister Sergey Lavrov on Saturday, expressing “strong concern that attacks today by armed militants in eastern Ukraine were orchestrated and synchronized, similar to previous attacks in eastern Ukraine and Crimea,” a senior State Department official said.
The official said Kerry warned Lavrov there would be “additional consequences” if Russia did not take steps to de-escalate the situation in eastern Ukraine and move its troops back from its border.
The official also noted that militants involved in Saturday’s unrest in eastern Ukraine “were equipped with specialized Russian weapons and the same uniforms as those worn by the Russian forces that invaded Crimea.”
The United States is prepared to step up sanctions against Russia if the recent actions in Ukraine continue, U.S. ambassador to the United Nations Samantha Power said on Sunday. Power said on ABC’s “This Week” the latest events in Ukraine bore “the telltale signs of Moscow’s involvement.”
“I think we’ve seen that the sanctions can bite. And if actions like the kind that we’ve seen over the last few days continue, you’re going to see a ramping up of those sanctions,” she said.
U.S. Vice President Joe Biden will travel to Kiev on April 22 to meet government leaders and members of the civil society.
NATO described the appearance in eastern Ukraine of men with specialized Russian weapons and identical uniforms without insignia — as previously seen in Crimea — as a “grave development.”
European Union foreign policy chief Catherine Ashton is to meet this week with foreign ministers from the United States, Russia and Ukraine in Switzerland to discuss efforts to de-escalate the situation.
In a written statement, she urged Moscow “to call back its troops from the Ukrainian border and to cease any further actions aimed at destabilising Ukraine.”
“The EU commends the Ukrainian authorities for pursuing their law and order operations in a measured way, in order to establish the authority of the state.”
EU foreign ministers will meet in Luxembourg on Monday to discuss the crisis.
CNN’s Tim Lister reported from Donetsk, Victoria Butenko reported from Kiev, Nick Paton Walsh reported from Kramatorsk, and Ralph Ellis wrote in Atlanta. CNN’s Marie-Louise Gumuchian, Carol Jordan and Brian Walker contributed to this report.
™ & © 2014 Cable News Network, Inc., a Time Warner Company. All rights reserved.