MILAN, March 12 (Reuters) - Milan prosecutors have requested trial for Amazon's AMZN.O European unit and four of its managers over alleged tax evasion worth around 1.2 billion euros ($1.38 billion), two sources with direct knowledge of the matter said on Thursday.

The move is unprecedented for a case of this kind in Italy, as Amazon agreed in December to pay 527 million euros, including interest, to Italy's Revenue Agency to settle the tax dispute.

In all previous cases involving other international groups, once a settlement was reached and payment made, prosecutors closed related criminal investigations, either through plea deals or by dropping the cases.

This time, however, Milan prosecutors did not share the tax authority's approach and decided to press ahead with their probe, leading to a request that the suspects be sent to trial.

Amazon was not immediately available for comment.

($1 = 0.8669 euros)

(Reporting by Emilio Parodi, editing by Crispian Balmer and Giselda Vagnoni)

((emilio.parodi@thomsonreuters.com; +39 06 8030 7744; Reuters Messaging:))