In Ukraine's autonomous Russian-majority region of Crimea, MPs have set up a referendum on its status.

According to the new proposal, it should be up to the Crimean population to decide whether to expand its autonomy and make choices upon its future, Russian agency ITAR-TASS has reported, citing parliamentary officials.

The decision was declared short after parliament and government headquarters in Crimea's capital Simferopol were seized by a pro-Russian faction on Thursday. Russian flags flew over the building and also over other institutions in the city, as the BBC reported. No government workers were allowed to enter their offices, and barricades were seen in front of the parliament.

The day before, tensions arose in the Crimean capital as parallel rallies of supporters, mostly Crimean Tatars and opposition to the new Ukrainian leadership, comprised by the Russian-speaking majority, led to scuffles outside Simferopol's parliament.

At a new rally that took place in Simferopol later on Thursday, Russian flags were waved, and chanting such as "We are Russia" could be heard across the streets. The centre of Simferopol was sealed off by police officers on Friday morning and afternoon.

Kiev's new leadership has pledged to keep Ukrainian territorial integrity and warned Russia against interference in its own domestic affairs.

Moscow, assuring it will not breach the sovereignty of Ukraine, has nevertheless put 150 000 combat troops on "high alert" at its Ukrainian border and has expressed readiness to react in case of violence.