LONDON (Reuters) - Trading and mining giant Glencore GLEN.L has lost its exclusive marketing rights for two of Libya's main crude oil export grades after holding them since late 2015, trading sources with direct knowledge said.

Slideshow ( 2 images )

The Switzerland-based firm had secured the rights to the Sarir and Messla grades when it was one of the few foreign companies willing to deal with the North African country during unrest that has wracked the country since 2011.

Glencore, which had exclusive rights on the two grades until the end of 2018, and Libya’s National Oil Corp (NOC) declined to comment.

In a sign of renewed international confidence in Libya's oil industry, BP BP.L and Royal Dutch Shell RDSa.AS returned to lifting directly from the country last year, initially taking other grades.

“Glencore lost exclusivity on Messla and Sarir,” one of the trading sources told Reuters, asking not to be named. “Companies like BP and Shell had their first Messla and Sarir allocation.”

A second trader said that now “anyone can get these grades.”

The two grades account for nearly a fifth of Libyan output that now stands at 953,000 barrels per day (bpd), still well below the pre-conflict level of 1.6 million bpd.

For a period when oil production fell even more sharply, those grades that are exported from the eastern Libyan port of Marsa el Hariga generated the bulk of state revenues.

Libya’s 220,000 barrel-per-day Ras Lanuf refinery, which is now idled, ran on the two grades.

The remainder of Libya’s crude streams have not been allocated exclusively to one company for such an extended period.

So far, Unipec was also allocated three cargoes from Marsa el Hariga in January, one source said, although the proportion taken of each grade by the trading arm of China’s Sinopec was not immediately clear.

BP is due to take 1 million barrels on the Crescent Moon tanker in mid-January from the same port, according to a shipping source and Refinitiv Eikon ship tracking. BP did not immediately respond to a request for comment.

Shell is also due to take at least one cargo from Marsa el Hariga, three sources said. Shell also did not immediately respond to a request for comment.

Security challenges still threaten Libya’s oil infrastructure. Its largest oilfield, El Sharara, has been shut since December over a dispute with tribesmen, armed protesters and state guards demanding salaries and development.