Ukraine crisis: Crowds march in eastern city as separatist unrest simmers (w/ video)DONETSK, Ukraine (CNN) -- Crowds marched through Ukraine's eastern city of Donetsk Thursday demanding greater autonomy, as a tense stand-off between pro-Russian militants and the interim government in Kiev shows no sign of easing.
By: Laura Smith-Spark and Arwa Damon, CNN
DONETSK, Ukraine (CNN) -- Crowds marched through Ukraine's eastern city of Donetsk Thursday demanding greater autonomy, as a tense stand-off between pro-Russian militants and the interim government in Kiev shows no sign of easing.
At the head of the march, held to mark May Day, was a speaker who blamed Kiev authorities for the unrest gripping the country's eastern region.
The government's actions have forced pro-Russian supporters to the point where they are demanding a referendum on May 11 and a federal state, he said.
Many in the region view the interim government as a "junta" which seized power thanks to backing from ultranationalist groups, and they are angered by its actions.
Eastern Ukraine was a heartland of support for pro-Moscow President Viktor Yanukovych, ousted in February after months of protests by people upset that he had turned away from Europe in favor of Moscow.
Pro-Russian protesters control key government buildings in Donetsk, after seizing them last month, and have declared it to be the "Donetsk People's Republic."
From the industrial city's Lenin Square, where the march started, masked men could be seen atop a building next to a flag signaling support for the pro-Russian camp. The yellow and blue Ukrainian flag, which had been flying until a short time before, was thrown off the side of the building, a symbol of the spreading unrest.
Pro-Russian protesters in the city of Luhansk, northeast of Donetsk and closer to the Russian border, said Wednesday that they had seized additional government buildings because they wanted to be sure of holding the planned referendum.
A representative of the activists, Oleg Desyatnichenko, told reporters they had given the local government an ultimatum Saturday about holding a referendum on greater autonomy for the region.
There was no response, he said, so the activists moved in. They took control of the buildings to gain access to resources, polling sites and voting lists.
Kiev rally for peace and unity
Acting Ukrainian President Oleksandr Turchynov acknowledged this week that the central government has effectively lost control of Ukraine's Donetsk and Luhansk regions to the pro-Russian separatists.
A controversial referendum in Ukraine's southeastern Crimea region in March resulted in its annexation by Russia, a step widely condemned by the international community.
Like Crimea, although not to the same extent, many in eastern Ukraine are Russian-speaking and have close cultural ties to Russia.
The crisis has sparked deep divisions in Ukraine. Many also want to see the country remain united but unhappiness over government corruption and ineffectiveness runs deep.
In Ukraine's capital, Kiev, on Thursday, hundreds of people joined a rally for peace and unity, organized by student and trade union groups and left-of-center parties.
The protesters called for constitutional reform, decentralization of power and new parliamentary elections.
They also called for a national referendum to decide whether Ukraine should become a federal state; if the Russian language should become the official language in some regions; and whether Ukraine should integrate with the European Union.
The protest has been peaceful, with no incidents reported so far.
Diplomat accused of spying
Meanwhile, Ukraine has ordered the expulsion of a Russian naval diplomat after alleged spying this week, Ukraine's Foreign Ministry said on its Facebook page Thursday.
The statement said the attaché was detained "while he was committing spying activities on April 30th."
The ministry said the diplomat has to leave Ukraine as soon as possible.
Ukraine and Western nations have accused Russia, which NATO says has tens of thousands of troops massed by Ukraine's border, of supporting and coordinating separatist unrest in its eastern region.
But Russia denies any direct involvement in the disorder, which has seen pro-Russian militia groups seize government and police buildings in more than a dozen towns and cities across the region.
Ukrainian military put on alert
Turchynov said Wednesday that the country's armed forces have been put on full combat readiness because of the threat from Russia.
Speaking at a meeting with the heads of regional state administrations, he said authorities' task was to prevent the spread of the "terrorist threat" from separatists and pro-Russian saboteurs to other regions of Ukraine. He accused groups in Slavyansk of "killing and torturing people, capturing people," and he said that in addition to automatic weapons, they had heavy weapons like grenade launchers.
He had earlier said that events in Ukraine's Donetsk and Luhansk regions had shown the authorities' "helplessness" to counter the separatists' activities.
A military "anti-terrorism" operation launched last month has achieved little or nothing.
The government in Kiev has said it wants to show restraint and appears reluctant to embark on military operations against militants who are embedded in residential areas.
Western nations have been seeking a diplomatic resolution to the crisis, in part by pressuring Russia to help disarm the illegal militia groups.
The European Union and United States say Moscow has not so far acted in support of an April 17 international deal aimed at easing the crisis and this week imposed additional sanctions on Russian officials and companies judged to be close to President Vladimir Putin.
Russia's Foreign Ministry responded to Turchynov's remarks late Wednesday by denouncing what it called "these militaristic statements of Kiev authorities."
"We insist on an immediate termination of the Kiev militaristic rhetoric aimed at intimidating its own population, on preventing the use of force and initiation of the internal Ukrainian dialogue to seek national reconciliation within the country," the ministry said in a statement posted on its website.
Meanwhile, militants in the town of Slavyansk continue to hold seven military observers from the Organization for Security and Cooperation in Europe, detained last Friday despite their diplomatic status.
Denis Pushilin, self-declared chairman of the "Donetsk People's Republic," told CNN Wednesday that they "would decide about them later."
He repeated the separatists' assertion that the observers are NATO spies and said they would like to exchange them for people detained by pro-Kiev authorities.
CNN's Arwa Damon reported from Donetsk and Laura Smith-Spark wrote and reported in London. CNN's Claudia Rebaza and journalist Victoria Butenko in Kiev contributed to this report.