* Assets previously seized from Nomura unfrozen -source
* Judge did not see fraud, deemed seizure not urgent -source
* Nomura declines to comment
By Silvia Ognibene
SIENA, Italy, April 27 (Reuters) - An Italian judge has rejected an order to seize around 1.8 billion euros ($2.3 billion) of assets from Nomura as part of a probe into suspected fraud involving troubled lender Monte dei Paschi di Siena, legal sources said on Saturday.
Assets worth 140 million euros that were already seized from the Japanese bank have been released under the judge's ruling, which was made on Friday, the judicial source said.
A spokeswoman for Nomura in Italy declined to comment.
Prosecutors in Siena investigating lossmaking derivatives trades made under Monte Paschi's previous management ordered the seizure of around 1.8 bln euros of assets from the Japanese bank on April 16, but the court has rejected their request to have the order endorsed.
The trades under scrutiny include a structured deal with Nomura known as 'Alexandria', as well as a similar trade with Deutsche Bank called 'Santorini' and a smaller deal called 'Nota Italia' with JP Morgan.
Judge Ugo Bellini ruled against the seizure because he did not see evidence of fraud and deemed there was no urgency in freezing the assets given that the contract dates back to 2009, an investigative source said.
It was not immediately clear whether under the judge's ruling Monte Paschi has to resume collateral payments on the Alexandria deal, which had been frozen by the prosecutors order.
On Friday Nomura's chief financial officer, Shigesuke Kashiwagi, said in a note that his bank intended to engage with Italian prosecutors to find a solution.
Monte Paschi was forced earlier this year to book losses of nearly 1 billion euros after disclosing details of the complex derivatives deals.
The bank had already been weakened by the euro zone crisis and has been forced to accept help from the state in the form of 4 billion euros of state bonds to meet tough capital requirements set by European regulators.
The investigation is also politically sensitive in Italy as the Tuscan bank had strong links with local centre-left party leaders.