Ukraine crisis: Russia MPs welcome Crimea referendum
The heads of Russia's two houses of parliament have said they will support Crimea if the region votes to leave Ukraine in a referendum on 16 March.
After meeting visiting Crimean MPs, Federation Council Speaker Valentina Matviyenko said the peninsula would be welcome as an equal part of Russia.
The interim government in Kiev has denounced the vote as "illegitimate".
Meanwhile, Russia's state-owned energy company, Gazprom, has warned Ukraine that its gas supply might be cut off.
CEO Alexei Miller said it was owed $1.89bn (£1.13bn) and warned: "Either Ukraine makes good on its debt and pays for current supplies, or there is risk of returning to the situation of early 2009."
Gazprom halted supplies to Ukraine for almost two weeks in 2009, a move that caused shortages in Europe.
Ukrainian officials have said the state has come close to bankruptcy since protesters ousted President Viktor Yanukovych at the end of February and pro-Russian forces took control of Crimea last week.
Officials say $35bn (£21bn) is needed to get through this year and 2015.
'Free and democratic choice'
In Moscow, Russian MPs gave a standing ovation to a delegation of politicians from Crimea, including parliamentary Speaker Vladimir Konstantinov, and promised to support their bid to make it part of Russia.
"Yesterday we learned about the historic decision taken by the Crimean parliament to hold a referendum on accession, on entry into the Russian Federation," said Ms Matviyenko.
"If the people of Crimea take the decision in the referendum to join Russia, we, as the upper house, will of course support such a decision."
The speaker of the lower house, Sergei Naryshkin, concurred.
"We support the free and democratic choice of the population of Crimea," he said.
More than 65,000 people attended a rally outside the Kremlin expressing solidarity with the pro-Russian authorities in Crimea, Moscow police said.
The BBC's Richard Galpin in Moscow says the Kremlin is steadily ratcheting up the pressure on the new government in Kiev, and appears to be preparing to annexe Crimea.
Ukraine's interim Prime Minister Arseniy Yatsenyuk said he was open to talks with Russia as long as it withdrew its troops and abided by international agreements.
But in a warning to the "separatist and other traitors of the Ukrainian state", he said: "Any decision of yours is deliberately unlawful and unconstitutional and no-one in the civilised world will recognise the decision of the so-called referendum of the so-called Crimean authorities".
Russian President Putin's spokesman, Dmitry Peskov, dismissed the calls for Western-mediated talks. He also warned that there was a risk of ethnic persecution in Crimea and eastern Ukraine if "those who stood behind the coup in Kiev" reached those regions.
The Russian foreign ministry also accused the EU of taking an "extremely unconstructive position" by halting talks on easing visa restrictions on Russian citizens and on a new pact to replace the 1997 Russia-EU Partnership and Co-operation Agreement.
'Lower the heat'
Earlier, 47 military and civilian observers from the Organisation for Security and Co-operation in Europe (OSCE) were prevented from crossing into Crimea by armed men guarding the Chungar checkpoint for a second consecutive day.
Meanwhile, Russian President Vladimir Putin said he hoped the Paralympic Winter Games in the Black Sea resort of Sochi would help "lower the heat of passions over Ukraine".
The Ukrainian team was represented only by a single athlete carrying the national flag at the spectacular opening ceremony on Friday evening.
Valeriy Sushkevych, head of the National Paralympic Committee of Ukraine, said its athletes had debated whether to boycott the Games but had decided to compete unless the "crisis were to escalate".
The team wanted to compete in order to remind the world of what was happening in Crimea and the presence there of Russian troops, Mr Sushkevych added. Moscow has insisted the soldiers wearing Russian uniforms - without insignia - are local self-defence forces.