In Donetsk, a Ukrainian flag replaces a Russian one over a government building once more.
The offices, located in the home city of ousted president Viktor Yanukovych, had been under control of pro-Russian forces since Monday.
Police were evacuating the building out of fears it had been booby-trapped.
But the tensions are far from over, as rival rallies are scheduled for Wednesday evening.
In Crimea, forces believed to be Russian have surrounded the main military bases in the area. The Ukrainian authorities confirmed two missile defence facilities have also been encircled.
The border guard service said Russian navy ships have blockaded both ends of the Kerch Strait between Crimea and Russia, although civilian shipping waterways remained open.
Moscow says the ships in Crimea are part of the Black Sea fleet.