Ukraine's ex-president Viktor Yanukovych, who has been put on the international wanted list, remains in the country, according to the deputy general prosecutor.
Mykola Golomcha said "We have information indicating Yanukovych is still in Ukraine."
He did not give further details of the whereabouts of the leader who has been missing since Friday when he fled Kiev. He is wanted by police in the country on charges of mass murder.
The revelation came as Pro-Russia separatists and supporters of Ukraine's new leaders came head to head outside Crimea's regional parliament before a key debate.
Around 2,000 people, many of them ethnic Tatars who are the indigenous group on the Black Sea peninsula, gathered outside the parliament building in Sevastopol in support of the 'EuroMaidan' movement which ousted President Viktor Yanukovich.
Meanwhile, several hundred pro-Russia demonstrators chanted their loyalty to Moscow and denounced the "bandits" who had seized power in Ukrainian capital Kiev.
Isolated skirmishes could be seen among the crowds and there were reports of missiles being hurled, but police appeared to be holding the two sides apart as the emergency session took place inside the parliament to discuss the crisis.
Riot police disbanded
Crimea was gifted to Ukraine in 1954 in the Soviet-era by then Soviet leader Nikita Khrushchev. With a part of Russia's Black Sea fleet based in the port of Sevastopol, it remains the only region of Ukraine where ethnic Russians dominate in numbers.
Russian President Vladimir Putin has ordered an urgent drill to test the combat readiness of the armed forces across western Russia.
"In accordance with an order from the president of the Russian Federation, forces of the Western Military District were put on alert at 1400 (10am Irish time) today," Interfax quoted Defence Minister Sergei Shoigu as saying.
Russia's foreign minister said the "nationalist and neo-fascist" sentiment in western Ukraine must be "decisively condemned".
Sergei Lavrov's warning came as Ukraine's acting interior minister said he had disbanded the elite Berkut riot police that protesters blamed for scores of deaths in last week's clashes.
Mr. Lavrov made his call to democracy watchdog the Organisation for Security and Cooperation in Europe, which he also said should condemn attempts by nationalists to ban the Russian language in Ukraine.
"Lavrov called on the OSCE to decisively condemn the rise of nationalist and neo-fascist sentiment in the west of the country, (to condemn) calls to ban the Russian language, to turn the Russian-speaking population into 'non-citizens' and to restrict freedom of expression," his ministry said in a statement.
References to fascism are evocative of the Cold War period, when authorities in the East routinely described the West as fascist.
It came as Ukraine's acting interior minister, Arsen Avakov, announced the end of the riot police unit involved in violence that left almost 100 people dead last week.
"The Berkut is no more," he wrote on his Facebook account.
"I have signed Decree No 144, dated February 25, 2014 on the dissolution of the Berkut special police units of civil defence."
Britain and the US had earlier sought to ease tensions, saying Ukraine should not be a battleground between East and West.
