MILAN- Italian borrowing costs jumped to their highest level in several years at an auction on Wednesday, as the euro zone bond markets brace for the European Central Bank monetary policy normalization.

The Treasury sold the top planned amount of 8 billion euros ($8.67 billion) over five BTP bonds.

It assigned 3.75 billion euros of a new BTP maturing on Aug. 15, 2025 at a 1.32% gross yield - the highest level since December 2018 - versus 0.57% at the previous auction over a note due on December 15, 2024.

It also placed 1.5 billion euros of a BTP due on Feb. 15, 2029 fetching a 2.04% gross yield - the highest level since May 2019 - compared with 1.47% at a mid-March auction.

The Rome-based Treasury sold 1 billion euros of a BTP maturing on Sept. 1, 2052 fetching a 2.89% gross yield - the highest level since April 2020 - compared with 2.162% reached last January via syndication.

Finally, it assigned a total of 1.75 billion euros over 10-, 20-year off-the-run BTP notes.

($1 = 0.9228 euros)

(Reporting by Sara Rossi, editing by Giulia Segreti)