June 9 (Reuters) - Exxon Mobil Corp said on Wednesday it has made a new discovery at Longtail-3 in the Stabroek Block offshore Guyana, as the U.S. oil major develops one of the world's most important new oil and gas blocks in the last decade.

Exxon operates the 6.6-million-acre Stabroek Block as part of a consortium that includes Hess Corp and China's CNOOC Ltd. It began production at the block in 2019.

The company, however, did not specify the size of the latest discovery's oil and gas reserves.

The latest find continues the consortium's long string of discoveries in Latin America's newest crude producing nation and underscores the importance of Guyana to Exxon for increasing its future oil output.

The Longtail-1 discovery in the Stabroek Block was drilled in 2018, encountering about 256 feet (78 meters) of high-quality, oil-bearing sandstone reservoir.

In April, Exxon said it made discovery at the Uaru-2 well in the Stabroek Block. (Reporting by Arunima Kumar in Bengaluru; Editing by Shailesh Kuber)