Unveiling its worst annual result in 20 years on Tuesday, the London-based oil company announced a net loss of $6.48 billion (5.97 billion euros) for 2015, compared with a net profit of $3.78 billion in 2014.

Earnings were hit by a $2.6-billion charge in the fourth quarter that was mostly linked to impairments in the upstream division, or exploration and production, as well as restructuring costs. Underlying replacement-cost profit, which excludes fluctuations in the value of crude oil inventories, more than halved to $5.9 billion.

In the final quarter of 2015 alone, the earnings measure tumbled to just $196 million, from $2.2 billion a year earlier.

"The lower underlying result was predominantly driven by the impact of steeply lower oil and gas prices on BP's upstream segment," the company said in a statement.

Job cuts amid price slump

Oil prices have crashed about 75 percent since mid-2014, hit by the slowing global economy, the strong US dollar, and a chronic supply glut that has been exacerbated by OPEC's refusal to curb output.

In the face of the crisis, energy companies across the world are cutting jobs and delay investments. On Tuesday, also announced it would reduce its workforce by 4,000 jobs this year in its upstream division, and up to 3,000 positions in its downstream business by the end of 2017.

BP chief executive Bob Dudley said the company was moving quickly to "adapt and rebalance BP for the changing environment," adding: "We're making good progress in managing and lowering our costs and capital spending, while maintaining safe and reliable operations and continuing disciplined investment into the future of our portfolio."

uhe/kd (AP, AFP, Reuters, dpa)