Deposed Ukrainian president Viktor Yanukovych said he remains the country’s president and commander-in-chief of its armed forces.

Speaking in Rostov-on-Don in southern Russia, Mr Yanukovych said he is sure that soldiers will not obey "criminal orders".

He said the presidential election set for 25 May is "absolutely illegitimate" and "illegal".

Mr Yanukovych remained unswayed in his argument that "extremists" had taken power in Kiev. 

He also said that Crimea is breaking away from Ukraine and blamed opponents who forced him from power for developments on the Black Sea peninsula.

In his statement to journalists, Mr Yanukovych also said that US financial aid to Ukraine would be illegal, saying that US law does not allow the government to aid "bandits".

Mr Yanukovych was ousted on 21 February after a three-month revolt against his rule.

Pro-Russian politicians in Crimea this morning voted for independence from Ukraine in a precursor to a referendum this weekend for the region to become part of Russia.

The local assembly approved a "declaration on the independence of the autonomous republic of Crimea and the city of Sevastopol" with 78 out of 81 politicians present voting in favour, the parliament's press service said.

Ukraine's parliament has warned the assembly it faces dissolution unless the referendum is called off.

It gave the Crimean parliament until tomorrow to call off the vote.

Analysis: Five steps towards annexation of Crimea

German Foreign Minister Frank-Walter Steinmeier said the European Union will start preparing further responses to Russia's actions in Ukraine if Moscow does not show signs of backing down by the weekend.

"We don't want confrontation but the action of the Russian side unfortunately makes it necessary for us to prepare, as I have just outlined to you," he said.

EU leaders have so far taken largely symbolic action in response, such as suspending talks on visa deals.

Chancellor Angela Merkel has said tougher sanctions like travel restrictions and asset freezes could follow if Moscow does not take up her proposal of an "international contact group".

Earlier, French Foreign Minister Laurent Fabius said sanctions against Russia could be imposed as early as this week if Moscow fails to respond to a proposition designed to calm the crisis.

Mr Fabius told radio station France Inter that a referendum in the Crimea region on joining Russia set for 16 March was illegitimate and that the annexation of the region by Russia would be illegal.

NATO in joint military exercises over eastern Europe

NATO began war games in Poland, with US jets due to join the exercises as a gesture of Washington's support for its eastern allies after Russia's intervention in Ukraine.

Without naming neighbouring Ukraine, Polish President Bronislaw Komorowski called on his country's political parties to safeguard defence spending at a time of budget constraints due to the "events to the east".

The joint patrol missions over Poland and the Baltic Sea have been operating for the past decade.

The United States says both the air drills in Poland and its joint Black Sea exercises with Romania and Bulgaria were planned before the crisis in Ukraine.

The military exercises are taking place from the military base at Lask in central Poland.

Poland is a NATO member and staunch US ally and has been alarmed at Russia's intervention in Ukraine.

The exercises normally use routine military aircraft, but at Poland's request they have been beefed up by F-15 fighter jets.

NATO will also begin flying sophisticated reconnaissance aircraft known as AWACs over Poland and Ukraine to monitor the situation in Ukraine.

The US guided missile destroyer, the USS Truxton, is due to take part in manoeuvres in the Black Sea with a Bulgarian frigate and three Romanian naval vessels.

However, the exercise has been delayed by a day due to bad weather, according to Bulgaria's Defence Ministry.

The moves come as Russia and the US trade conflicting interpretations of recent diplomatic manoeuvres.

Russia said what it describes as a coup in the Ukrainian capital could not be the starting point of any negotiations.

The US has insisted that Russian troops withdraw to their bases in Crimea and agree to engage with the new government in Kiev.