A new study by the U.S. Army War College has concluded that Al-Qaeda will focus on launching terrorist attacks on the homeland and overseas that hurt the U.S. economy, the intelligence newsletter Geostrategy-Direct.com has reported.

"Al-Qaeda leaders learned many important lessons from the 9/11 attacks and will likely continue with a terror campaign focused on soft targets that greatly impact the American people economically and will attempt to make this a long, endless struggle and violent clash of civilizations that cannot be won by the United States," the report said.

The study concluded that Al-Qaeda will focus on attacking "soft targets," which are targets that are difficult to defend and relatively easy and cheap to attack. A key part of this strategy, the study said, is to "ensure the Muslim world is inhospitable for U.S. business."

"Terror attacks on our subways, railways, and the airline industry will certainly create hysteria, cause panic, and incite fear while costing the United States millions of dollars. Attacks within the Middle East against oil infrastructure or shipping would wreack havoc in world markets as well as cause skyrocketing crude oil prices, further causing economic backlash as global markets scramble to absorb these blows," the report said.