Pakistan and the United States have signed an agreement outlining the movement of NATO supply convoys through Pakistan and into Afghanistan.

The deal signed Tuesday formalizes an arrangement that has allowed the U.S. to supply its troops fighting in the Afghan war for over a decade.

Earlier this month, Pakistan re-opened its two border crossings into Afghanistan following a seven-month shutdown. Islamabad closed the NATO supply lines after U.S.-led coalition airstrikes mistakenly killed 24 Pakistani troops near the Afghan border.

U.S. and Pakistani officials signed the Memorandum of Understanding during a cermemony Tuesday in Rawalpindi.

On Wednesday, Pakistan's spy chief is set to meet with his American counterpart in Washington.

Inter-Services Intelligence agency head Lieutenant General Zaheerul Islam is expected to hold counterterrisom cooperation and intelligence sharing talks with CIA director David Petraeus.