Ukraine’s acting President Oleksandr Turchynov had already ordered increased security at key sites, including nuclear plants.
Meanwhile President Barack Obama has called the Russian decision a “violation of Ukrainian sovereignty”.
Ukraine has said it will seek the help of US and UK leaders in guaranteeing its security. NATO has called emergency talks to be held on Sunday at 12:00 GMT.
The new Ukrainian PM Arseniy Yatsenyuk has warned that military action by Moscow would be “the beginning of war and the end of relations”.
Heavily armed groups continue to occupy key sites in Crimea, including airports and communications hubs, although there has been no actual violence.
ZWPqsv_2IhkThe US House Ethics Committee has voted to release its report on former Republican Representative…
ABC News has agreed to pay $15 million to President-elect Donald Trump to settle a…
South Korea’s parliament has voted to impeach President Yoon Suk Yeol over his failed attempt…
Israeli war planes have carried out more than 100 air strikes in Syria on December…
President-elect Donald Trump has threatened to impose 100% tariffs on the BRICS countries if they…
Syrian troops have withdrawn from the city of Aleppo following an offensive by rebels opposed…