Adds details from paragraph 3

By Elvira Pollina

MILAN, June 24 (Reuters) - Telecom Italia (TIM) TLIT.MI has filed a case with a Milan court against new grid tariffs set by KKR-backed FiberCop, to whom TIM sold its telecoms network in 2024, two sources said.

TIM decline to comment. FiberCop was not immediately available to comment.

The dispute centres around the terms governing TIM's access to the fixed-line network assets it sold to a KKR-led consortium as part of a broader restructuring aimed at slashing TIM's debt by 14 billion euros.

The court complaint was filed under a fast-track procedure, with a first hearing on the case scheduled in early July, two people with knowledge of the matter told Reuters on condition of anonymity because the matter is not public.

A third person said that the new tariff scheme entails dozens of million of euros each year in additional costs for TIM, which now pays to use the grid it once owned.

FiberCop, which operates Italy's main telecommunications landline network, is 37.5% owned by U.S. investment firm KKR, with the Italian Treasury holding a 16% stake.