Algerian state energy firm Sonatrach has resumed operations in neighbouring Libya after suspending work because of last year's uprising.
"Now our presence is effective in this sister country. Our operations have resumed, in particular for drilling," Sonatrach Chief Executive Abdelhamid Zerguine told a news conference.
Sonatrach has exploration rights in the Ghadames basin, near the border between the two countries.
Foreign companies are gradually returning to Libya, despite concerns over security and about the possibility that the new authorities will review contracts signed during the rule of ousted leader Muammar Gaddafi.