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President Donald Trump's travel ban, which triggered days of chaos before being dealt a blow in the courts that effectively suspended its execution, still has thousands of immigrant students stranded in a state of limbo. After a three judge panel of the Ninth Circuit Court of Appeals blocked the immigration order, which imposed travel restrictions on citizens from seven majority-Muslim countries linked to terrorism, Trump vowed to issue a new executive order that could come as early as next week. With the world watching for Trump's latest moves, international students who hail from the countries affected by the ban are on tenterhooks, waiting for the other shoe to drop. "I hope the ban is not extended beyond the 90-days period" said Mostafa Afkhamizadeh, a PhD candidate from Stanford University who was initially banned from coming back to California when traveling from his native Iran. Afkhamizadeh traveled to his home country on January 19th, but was held up by Trump's executive order. He now finds himself trying to get back, much like thousands of other U.S. green card and visa holders who found their ability to travel was curtailed by the original ban. "I'm mostly concerned about further policy changes or a revised executive orders during my visa process" the engineering student said to CNBC recently, who is waiting for a visa appointment in March. If Trump issues a new order that is upheld, "I will most likely terminate my doctoral program." More than 1 million strong

Trump's immigration ban impacted more than 16,600 students in the U.S., according to figures from the Institute of International Education, a vital pool of talent that boosts economic activity in ways both large and small.

The more than 1 million international students living domestically contribute nearly $33 billion to the U.S. economy, according to NAFSA: Association of International Educators. The majority graduate to become professionals, researchers and innovators for U.S. employers. They make up more than 70 percent of graduate students in electrical engineering and computer science and support more than 400,000 jobs in the U.S., according to NAFSA data. That group includes Abdallah, a Palestinian computer science student in California who spoke to CNBC recently, but asked not to share his full name. Like many students, Abdallah voiced concerns about whether he'd be allowed to continue his studies.

"The future is very uncertain, and we don't know whether the ban is going to expand, or people from other Muslim majority countries are going to suffer" with tighter restrictions being extended to other countries, Abdallah told CNBC.