WASHINGTON (CNN) - The United States is sending $100 million in aid to Pakistan to help alleviate the plight of an estimated 2 million people displaced by recent fighting against Taliban extremists, Secretary of State Hillary Clinton announced Tuesday.
The money comes on top of $60 million in assistance already provided by the United States to Pakistan since last August.
The assistance is "essential to the global security and security of the United States," Clinton said in a White House briefing. Much of the aid will be directed toward the purchase of Pakistani grain as part of a larger "investment in the people and economy in Pakistan."
The Pakistani government is helping to lead the fight against extremists threatening "our collective security" and therefore deserves to be supported, she argued.
Clinton called on individual Americans to support the relief effort in the form of $5 donations by texting the word "SWAT" to the number 20222.
Much of the recent fighting has been centered in and around Pakistan's Swat Valley.
The aid could begin arriving in Pakistan this week if Islamabad grants permission for the C-17 flights, U.S. defense officials said earlier Tuesday.
The aircraft will carry food, water, water trucks and air-conditioned tents, the officials said.
Planning has been under way for several days, but Pakistani officials are sensitive to U.S. military presence in their country, the officials added.
Pakistan's military has waged a massive operation against Taliban militants in the country's northwest region. Pakistanis are fleeing the ongoing fighting in "the biggest and fastest exodus that we have seen in recent years," United Nations refugee agency spokesman Ron Redmond said.
Nearly 1.5 million Pakistanis have registered as displaced since May 2 - a rate of about 85,000 people fleeing a day - Redmond said. The total number is equivalent to the population of Philadelphia, Pennsylvania.
-CNN's Barbara Starr contributed to this report