* Shares and bonds rise, rouble gives up gains
* Brent crude up 3 pct
* Rosneft repays $7 billion loan tranche (Updates prices, adds CDS)
By Alexander Winning and Vladimir Abramov
MOSCOW, Feb 12 (Reuters) - Russian assets strengthened on Thursday after leaders at peace talks in Minsk agreed a deal to halt fighting in eastern Ukraine, but the rouble's bounce was short-lived as currency dealers saw foreign currency purchases pick up.
Moscow's dollar-denominated RTS index was up 2.5 percent at 853 points, while its rouble-based peer MICEX was 2 percent higher at 1,797 points at 1420 GMT.
Russian Eurobonds, meanwhile, rose across the curve , with the yield on the benchmark 2030 dollar bond falling 32 basis points to 6.06 percent.
The rouble initially jumped before sliding to 66.46 to the dollar, around 1.9 percent weaker than the previous close. It was 2 percent weaker against the euro at 75.44.
A currency dealer at a Western bank said a large player could be closing positions opened earlier in the session, and that algorithmic trading programmes could be playing a role.
Analysts said an onerous burden of foreign debt repayments could also be driving Russian firms to buy dollars on the market. Russian firms have around $36.5 billion in gross foreign debt repayments due in February and March, according to central bank data.
Participants at the Minsk summit, attended by the leaders of Ukraine, Russia, Germany and France, as well as pro-Russian separatists fighting in eastern Ukraine, said the ceasefire would come into force on Feb. 15, followed by the withdrawal of heavy weapons.
Russian President Vladimir Putin said the sides had agreed on the "main issues". German Chancellor Angela Merkel said Putin had put pressure on the separatists to agree to the ceasefire, but that "very much work" still needed to be done.
Despite the remaining hurdles to a lasting peace, the cost of insuring exposure to Russian debt via credit default swaps fell to a near-six week low, according to financial data provider Markit.
Brent crude rose over 3 percent on Thursday to $56.50 a barrel, underpinning Russian asset prices.
Market sentiment was boosted by top oil producer Rosneft , which said it had repaid a $7 billion tranche of a two-year bridge loan.
Rosneft, whose access to international capital markets is restricted by Western sanctions, said it had not bought foreign currency on the market to make the payment.
A debt repayment by Rosneft in December coincided with a dramatic collapse in the rouble, leading some in the market to believe the oil company was partly responsible.
Rosneft has denied any hand in the rouble's weakening, despite the head of the central bank describing a bond placement by Rosneft in December as "not transparent" and a cause of currency volatility.
For rouble poll data see
For Russian equities guide see
For Russian treasury bonds see
Russia in graphics: link.reuters.com/dun63s (Editing by Jason Bush and Gareth Jones)