California's Air Resources Board (CARB), which monitors air pollution in the western US state, said on Thursday it would fine Volkswagen an extra $154 million (132 million euros) in penalties and costs.

The sum brings to $1.3 billion the total settlement VW must pay to Califorina over the so-called "Dieselgate" scandal, which saw the Wolfsburg-headquartered carmaker intentionally program software in its diesel engine cars to evade emissions tests.

The fines will go towards helping the state boost its use of cleaner-running electric cars, US media said.

The additional settlement announced on Thursday still requires court approval.

Hint of more fines

CARB's chair Mary Nichols said while the payment "closes another chapter" in the affair, "it is not the end of the story."

Nichols said some consumers were still waiting to know what would happen to their cars, and that her organization would work with the US Environmental Protection Agency to see if some vehicles can be retrofitted.

VW agreed to buy back hundreds of thousands of diesel vehicles after California rejected a plan to recall and refit some of the cars. But thousands are reported to be still waiting for their refunds.

Read more: New EU car emissions tests slammed as 'paper tiger'

Volkswagen has admitted the emissions cheat was installed in some 11 million vehicles, including more than half a million in the US. The defeat devices allowed its vehicles to continue spewing toxic particles far above legal limits.

Environmental regulators say some VW vehicles emitted up to 40 times the allowed levels of nitrous oxides when on the road.

Huge losses

Earlier this year, it agreed to pay a $4.3bn settlement to the US government, while globally the scandal is likely to cost the firm some 22 billion euros or more to settle fines and compensation.

VW still faces many legal challenges in Germany and several other countries as well as private lawsuits.

Read more: Merkel testifies that she knew nothing of VW 'Dieselgate' in advance

The scandal has also led to greater scrutiny of the emissions of VW's other brands, including Porsche and Audi and their competitors.

Earlier this week, another German manufacturer Daimler - which owns the Mercedes Benz brand - recalled some 3 million cars to adjust the amount of pollutants emitted by their diesel engines.

mm/bk (AFP, AP)