OREANDA-NEWS. A bomb exploded close to a pipeline carrying crude from a major oilfield near Iraq's northern city of Kirkuk, according to security and oil sources who said exports to Turkey were not affected.

The bomb blast occurred near a pipeline running from an oil well in Bai Hassan oilfield, which currently produces around 125,000 barrels per day (bpd), causing minor damage, officials at the state-run North Oil Company (NOC) said.

Police also defused three other makeshift bombs planted near a pipeline network close to the site of the explosion, security sources said.

The blast did not affect exports via the Kirkuk-Ceyhan line, which average around 330,000 bpd, but the attack shows the vulnerability of Iraq's oil infrastructure in an area where militant groups are active.

No group claimed responsibility for the attack but several armed factions are active in Kirkuk, and Sunni Islamist insurgents linked to al Qaeda often strike at security forces and energy installations in an attempt to undermine the Shi'ite-led government.

Saturday's attack was the fourth time the Bai Hassan oilfield has been targeted since June 2012.

Crude oil flows from the OPEC member to Turkey on the Kirkuk-Ceyhan pipeline have been repeatedly disrupted this year due to attacks which have left the major line all but idled.

The bulk of Iraq's oil is exported from the southern terminals of Basra, but just below 400,000 bpd - a quarter of all exports - is pumped through the Kirkuk pipeline to Ceyhan port in Turkey.