Authorities in northern Mali say at least four rebels are dead after a Dutch attack helicopter with the U.N. mission fired upon their car.

The violence took place near Tabancort north of the town of Gao and is the first time that the U.N. mission, known as MINUSMA, carried out such air strikes.

Alhousseini Ag Goumeye, a military official with the Tuareg separatist rebel group NMLA, said six missiles were fired on the car, killing four militants.

In a statement, MINUSMA said its forces had to fire Tuesday after they came under "direct heavy fire." It said the action was in line with its mandate to use force to protect civilians and urged the rebels to respect a cease-fire.