At least one wounded as Russian troops storm Crimea
Pro-Russian forces stormed a Ukrainian air force base in Crimea, firing shots and smashing through concrete walls with armoured personnel carriers, according to an Associated Press journalist.
At least one person was wounded, the base commander said.
An APC also smashed open the front gate of the Belbek base near the port city of Sevastopol, according to footage provided by the Ukrainian Defence ministry. Two ambulances arrived and then left shortly after. At least one of them was carrying what appeared to be a wounded person.
The Ukrainian commander of the base, Yuliy Mamchur, said there was at least one injury. He called his men together, they sang the Ukrainian national anthem and then stood at ease. He said they are going to turn over their weapons.
Russian forces have been seizing Ukrainian military facilities for several days in the Black Sea peninsula, which voted a week ago to secede and join Russia.
Elsewhere, more than 5,000 pro-Russia residents of the city of Donetsk in Ukraine's east demonstrated in favour of holding a referendum on whether to seek to split off and become part of Russia. The rally came less than a week after the Crimea referendum. After the vote Russia moved to formally annex Crimea.
With Crimea now effectively under the control of Russian forces, which ring Ukrainian military bases on the strategic Black Sea peninsula, concern is rising that Ukraine's eastern regions will push for a similar move.
Russia has brought large military contingents to areas near the border with eastern Ukraine. Russian President Vladimir Putin has said there is no intention to move into eastern Ukraine, but the prospect of violence between pro- and anti-secession groups in the east could be used as a pretext for sending in troops.
Eastern Ukraine is the heartland of Ukraine's economically vital heavy industry and mining and the support base for Viktor Yanukovych, the Ukrainian president who fled to Russia last month after being ousted in the wake of three months of protests in the capital, Kiev.
Russia and Yanukovych supporters contend Mr Yanukovych's ousting was a coup and allege that the authorities who then came to power are nationalists who would oppress the east's large ethnic Russian population.
About an hour after the Donetsk rally began, the crowd marched through the city center and assembled before the regional administration building chanting: "Crimea! Donbass! Russia!"
Demonstrators waving Russian flags were faced off by lines of shield-wielding riot police. Inside, German Foreign Minister Frank-Walter Steinmeier was meeting local officials.
The demonstrators erected several tents. "I'm ready to live in a tent, but I'm not ready to submit to the West, to dance to their tune," said Viktor Rudko, a 43-year-old miner.
The local parliament on Friday formed a working group to develop a referendum similar to the one in Crimea. Activists today passed out mock ballots, although no referendum has been formally called.
A number of leading pro-Russian activists have already been detained by police on suspicion of fomenting secessionist activities. The country's security services said they have arrested Mikhail Chumachenko, leader of the self-styled Donbass People's Militia, on suspicion of seeking to seize authority.
As tensions roil in the east, the Organisation for Security and Cooperation in Europe is deploying an observer team aimed at easing the crisis.
Russian Foreign Ministry spokesman Alexander Lukashevich said on Friday that Moscow hopes that the 200-strong team "will help to overcome the internal Ukrainian crisis" and ensure the respect for human rights there.
It is unclear whether the team will be allowed into Crimea.
Mr Lukashevich said today that the OSCE's mission "will reflect the new political and legal order and will not cover Crimea and Sevastopol which became part of Russia."
Daniel Baer, the United States' chief envoy to OSCE, said the observers should have access to the territory because Crimea remains Ukrainian to the rest of the world.
The seizure of military facilities and navy ships by pro-Russian forces in Crimea has been proceeding apace since the peninsula was this week nominally absorbed by Russia.
Today a crowd stormed the Novofedorivka base, some 50 kilometres (30 miles) west of Simferopol, Ukraine's Defence Ministry said.
Ukrainian television station TSN said troops inside the base hoisted smoke grenades in an attempt to disperse groups of burly young men attempting to break through the front gates.
TSN reported that there were children among the crowd attempting to seize the base.