CAIRO (Reuters) – Libya’s National Oil Corporation (NOC) said on Saturday that revenues rose to more than $1.5 billion in March, up 20 percent from the previous month, but that fighting between rival factions posed a serious threat to production.

The $270 million rise in revenue was mainly due to the ending of a three-month armed blockade at the south-western oilfield of Sharara, NOC said in a statement.

But the state-run firm said fighting around the capital Tripoli, where forces loyal to Khalifa Haftar launched an offensive early this month, put future output at risk.

“The latest outbreak of hostilities … poses a serious threat to our operations, production and the national economy,” said NOC Chairman Mustafa Sanalla.

“The corporation is gravely concerned about the threat to national energy infrastructure and attempts to use NOC facilities and equipment for military purposes,” he added, calling for an “immediate cessation of hostilities”.

Possible fuel shortages would impact both the civilian population and NOC operations, Sanalla said.

Non-essential NOC staff living and working near conflict areas have been ordered to stay at home.

OPEC member Libya’s oil production has been repeatedly disrupted by conflict and blockades since the 2011 uprising that toppled former leader Muammar Gaddafi.