Pro-Russian forces stormed a Ukrainian air force base in Crimea, firing shots and stun grenades and smashing through concrete walls with armoured personnel carriers. 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 departed shortly after, and at least one of them was carrying what appeared to be a wounded person.
The Ukrainian commander of the base, Col. 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 then told his men to put their weapons in the base's armoury.
The men who stormed the base didn't wear any insignia. A Defence Ministry spokesman, Vladislav Seleznev, said on Facebook that they were part of the local militias that have been formed over the past several weeks, but their machineguns and APCs appeared to indicate a military connection.
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.
Also Saturday, a crowd stormed the Novofedorivka base, about 50 kilometres (30 miles) west of Simferopol, Ukraine's Defence Ministry said.
Ukrainian television station TSN said troops inside the base hurled smoke grenades in an attempt to disperse groups of burly young men attempting to break through the front gates.
Elsewhere, more than 5,000 pro-Russia residents of a major city 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 in Donetsk came less than a week after the Ukrainian region of Crimea approved secession in a referendum regarded as illegitimate by Western countries. After the referendum, Russia formally annexed Crimea.
With Crimea now effectively under the control of Russian forces, which surround Ukrainian military bases on the strategic Black Sea peninsula, concern is rising that Ukraine's eastern regions will agitate 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.
However, Valentina Matvienko, the speaker of the upper house of the Russian parliament and a close Putin ally, said Saturday that there is no intention to absorb other regions of Ukraine, according to the ITAR-Tass news agency.