Libya's National Oil Corporation has written to OPEC to complain about help fellow member Qatar is giving to Libyan rebels, sources familiar with the matter said on Monday.
The complaint by Shokri Ghanem, the chairman of NOC, hints at rising political tension as a result of the Libyan crisis within the Organization of the Petroleum Exporting Countries, which pumps more than a third of the world's oil.
"This is very unfortunate," said one of the sources, who declined to be identified because the source is not authorised to speak to journalists.
The 12-member OPEC has decided against taking any formal action on raising its production in response to the loss of Libya's oil exports and it is not scheduled to meet until June.
Still, Saudi Arabia and some other members have informally raised output, helping to make up for lost supply.