By Ayla Jean Yackley

ISTANBUL, Aug 11 (Reuters) - Turkish fire-fighters on
Wednesday battled to contain a raging fire on a pipeline
carrying about a quarter of Iraq's crude oil exports, a day
after an explosion blamed on Kurdish militants, officials said.

The bomb attack stopped the flow of oil on Tuesday on the
Kirkuk-Ceyhan pipeline and killed two people and wounded a third
after their vehicles caught fire on a road that runs alongside
the link.

"The fire continues, and the flow of oil has been halted.
Efforts are centred on putting out the flames," said a
spokeswoman for Botas, Turkey's state-run pipeline operator.

The bombing, which occurred about 100 kilometres (62 miles)
from the Iraqi border on Tuesday at 1530 GMT, was the second
attack on the pipeline in Turkey in less than two months.

In July, Kurdistan Workers Party (PKK) guerrillas said they
bombed the link, interrupting flows for several days.

Officials blamed the PKK for the latest bombing too.

Sabotage against the crucial energy corridor is still
comparatively uncommon on the Turkish side of the border.

In Iraq, following the U.S.-led invasion in 2003, attacks by
insurgents and technical problems kept the route largely closed
until three years ago.

Investigators on Wednesday defused two other bombs
discovered along the pipeline near where the blast occurred,
according to security officials, who declined to be identified.

A source from the Iraqi state-owned North Oil Company (NOC),
which operates the Kirkuk field, said daily oil exports through
the pipeline had recently been at 350,000 to 450,000 barrels per
day.

The source said pumping through the pipeline is expected to
resume only after it has been repaired.

TANKERS WAITING

Two tankers were waiting to load Iraqi cargoes at Ceyhan,
shippers said.

The 960 kilometre Kirkuk-Ceyhan link consists of two
parallel pipelines and carries an average 500,000 barrels of oil
a day to Ceyhan, where it is loaded onto tankers.

When the larger, main line is damaged, Iraqi officials can
use different pumping stations located along the route within
Iraq to switch the flow of crude to the other line, oil industry
sources have said.

One shipper said he was informed that efforts are underway
now to switch oil from the larger pipeline to the smaller one
and that the flow may resume later on Wednesday.

The PKK, which has waged a 26-year insurgency against the
Turkish state, in the past has targeted strategic assets such as
railways and pipelines.

In 2008, guerrillas said they bombed a BP-led line carrying
Azeri crude that halted flows for almost three weeks, driving up
world oil prices.

The conflict between the PKK and Turkish military, which
began in August 1984 as a campaign for an independent Kurdish
homeland, has claimed more than 40,000 lives, mostly Kurdish.

Violence has risen this year after the militants called off
a unilateral, 14-month ceasefire in June.

More than 100 military personnel have been killed since
March, already exceeding the death toll in all of 2009.

(With additional reporting by Walid Ibrahim in Baghdad)

(Additional reporting by Seyhmus Cakan in Diyarbakir,
Turkey; Editing by Simon Cameron-Moore and Jane Baird)