(Adds details, fuel tanker at Hariga port, background)
By Feras Bosalum and Ayman al-Warfalli
TRIPOLI/BENGHAZI, Libya, April 26 (Reuters) - A strike by Libyan security guards over salary payments has forced the closure of the western El Feel oilfield, a spokesman for state oil firm NOC said on Sunday.
On Saturday, a field engineer told Reuters the OPEC producer had closed the field, without citing a reason. El Feel is operated by a joint venture owned by NOC and Italy's Eni .
"The field's security guards are on strike because they complain about a delay of their salary payments," said Mohamed El Harari, a spokesman for NOC.
"NOC paid the salaries to the security forces, but they haven't paid the guards yet," he said.
Libya this year had managed to restart El Feel, which analysts say produced about 100,000 barrels per day (bpd). Libya had to shut the field late last year when a group in the Zintan region, which opposes a self-declared government in Tripoli, closed a pipeline.
Harari did not give any production figure, but the latest closure is likely to reduce national output to well below 500,000 bpd, a third of the volume Libya used to pump in 2010 before an uprising toppled Muammar Gaddafi and sent the country into turmoil.
On the bright side, eastern Libyan state firm AGOCO, a unit of NOC, is producing 270,000 bpd, a company spokesman said on Sunday.
"We face no problems at our fields or ports," he said.
Its Hariga port, fed by AGOCO's Sarir field, the country's biggest, on Sunday was expecting a tanker to lift 630,000 barrels of crude, another oil official said. A second tanker was bringing imported fuel.
Another tanker was docked at the eastern Zueitina port, run by a different state oil firm, to lift 650,000 barrels of crude, a third official said.
The 340,000 bpd El Sharara oilfield near El Feel remains closed, since the Zintani group shut operation of a pipeline.
The group is allied to Libya's officially recognised government, which has been working out of the east since losing control of the capital in August. (Writing by Ulf Laessing; editing by William Hardy and Jane Baird)