WASHINGTON — President Barack Obama today called for first-ever mileage and emissions standards for big rig and work trucks, seeking to limit pollution from the large vehicles.

With a presidential memorandum signed in the Rose Garden, Obama also ordered federal agencies that have already brought out new standards for cars and light trucks for the 2012-2016 model years to begin work on even stronger rules for 2017 and beyond.

"The disaster in the Gulf only underscores that even as we pursue domestic production to reduce our reliance on imported oil, our long-term security depends on the development of alternative sources of fuel and new transportation technologies," the president said.

The directive calls for the development of new technologies to promote plug-in hybrids and electric vehicles and a diversified fuel mix including more biofuels and natural gas.

The Union of Concerned Scientists, an environmental advocacy group, said large trucks represent only 4 percent of all vehicles on U.S. highways but consume more than 20 percent of on-road transportation fuels. Obama wants standards developed for these vehicles beginning in the 2014 model year, and lasting through 2018.

Obama last month rolled out new standards for cars and light trucks for the 2012-2016 model years that aimed at reaching a fleet average of 35.5 miles per gallon by 2016, nearly 10 miles per gallon more than the current average.