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By Humeyra Pamuk

ISTANBUL, Feb 23 (Reuters) - A pipeline carrying crude oil from northern Iraq to Turkey is not expected to resume deliveries until at least Feb 29 due to security issues, a shipping source said, extending one of its longest outages in two years.

The pipeline, which carries around 600,000 barrels per day (bpd) of crude to the Turkish port of Ceyhan from fields in Iraq's Kurdish north and Kirkuk, has been halted since Feb. 17.

Iraq's autonomous Kurdistan region, which depends on revenue from oil exports via the pipeline, is struggling to avert economic collapse brought on by a global slump in crude prices.

"We were told that the pipeline would not be on line until at least Monday," the source told Reuters on condition of anonymity because the information has not been made public.

Turkish officials were not available for immediate comment.

Industry sources have said the pipeline was sabotaged. The shipping source told Reuters that crude flows had been turned off.

There has been renewed conflict between Turkey and the militant Kurdistan Workers' Party (PKK) after a ceasefire fell apart last summer.

The pipeline has been sabotaged several times inside Turkey in theft attempts and the KRG has also accused the PKK of targeting it. Although both Kurdish, the PKK opposes the KRG's economic relations with its foe, Turkey.

An industry source said security forces are clearing mines in the Sirnak area through which the pipeline runs.

Kurdish oil flows have been a boon for European refiners over the past year with trading sources calling Kurdish crude the most attractively priced in a market already oversupplied with grades from Russia and the Middle East thus spoiling oil refiners for choice.

As a result of the outage, Iraq's state-run North Oil Company (NOC) which operates the Kirkuk fields has been forced to cut production to around 120,000 bpd from 200,000 bpd, a company official told Reuters on Saturday.

It is currently pumping around 30,000 bpd to the small refinery in Kirkuk and diverting around 70,000 bpd to storage depots near the city.

(Reporting by Humeyra Pamuk; additional reporting by Isabel Coles; editing by David Dolan and Jason Neely) ((humeyra.pamuk@thomsonreuters.com; +90 212 3507062; Reuters Messaging: humeyra.pamuk.reuters.com@reuters.net))