Federal regulators approved the first increase in US fuel economy regulations in nine years on Tuesday, requiring vehicle makers to increase the average fuel efficiency of light trucks by 1.5 miles per gallon by 2007, the Detroit News reported.

The paper said the new regulation --first proposed in December -- will require light truck fleets to average 21.0 mpg in the 2005 model year, 21.6 mpg in 2006 and 22.2 mpg in 2007. Currently, light trucks must average 20.7 mpg.

According to the Detroit News, the National Highway Traffic Safety Administration estimates the target will save 3.6 billion gallons of petrol  over the lifetime of the trucks sold during the three years.

The regulation represents the biggest jump in fuel economy requirements in the last 20 years, the paper said, citing NHTSA administrator Dr. Jeffrey Runge.

"The Bush administration is committed to improving vehicle fuel economy while protecting passenger safety and American jobs," Runge said, according to the Detroit News.

The paper said that environmentalists sought tougher rules due to the increasing popularity of less fuel efficient sport utility vehicles and pickups while General Motors, which sells more light trucks than any other vehicle maker, strongly opposed the new rule and claimed it would cost $US1.1 billion to implement.

According to the Detroit News, the NHTSA said the benefits to consumers would be greater than the cost burden the motor industry would face to meet the new rules.