The United States seeks new supply routes to Afghanistan after Pakistan closed its airspace.

Pakistan's decision means that Central Asia remains the only overland route to Afghanistan for the NATO.

The U.S. military is now preparing to boost cargo transportation through the highways, rail and air routes that run between the Baltic Sea and Afghanistan via the Caucasus and Central Asia - the so-called Northern Distribution Network, APA reports citing BBC World.

Pakistani authorities closed the supply routes on November 26.