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MINSK, Feb 25 (Reuters) - A potential deal between leading oil producers to freeze output should last for at least a year, Russian Energy Minister Alexander Novak said on Thursday.

Russia and OPEC members Saudi Arabia, Qatar and Venezuela agreed last week to work on a global deal to freeze oil output at January levels if other producers follow suit in a bid to tackle the global crude glut and support prices.

Novak told reporters in Minsk on Thursday it was unclear whether the proposed output freeze would be just a verbal agreement or a signed document.

"We don't yet know what format the agreements will take - whether an agreement or just statements and monitoring of the situation over several months," Novak said.

"We think that it is needed for at least a year. But in order to understand how it works, one needs to live under such agreements for several months at least," he said.

Moscow hopes that the oil market will balance faster if Russia and other countries do not increase output, Novak said.

He said oil ministers from OPEC and non-OPEC countries were planning to meet in mid-March and that Russia would attend the meeting if it took place. Novak said he would also probably meet with Iran's oil minister in March.

Iran is seen as the biggest obstacle to a deal to limit crude production. It is planning to ramp up its oil output following the end of Western sanctions and has said the output freeze proposal is "laughable".

(Reporting by Darya Korsunskaya; writing by Polina Devitt and Alexander Winning; editing by David Clarke) ((Polina.Devitt@thomsonreuters.com; +7 495 775 12 42; Reuters Messaging: polina.devitt.reuters.com@reuters.net))