Fewer international students are studying in the United States since the September 11, 2001 terrorist attacks. U.S. lawmakers and educators fear the trend could have an impact on U.S. competitiveness and even national security.

At a Senate Foreign Relations Committee hearing, Purdue University President Martin Jischke highlighted the problem his institution in the Midwestern state of Indiana and others around the country are facing in terms of declining numbers of foreign students.

"In the data collected earlier this year for the fall 2004, the 25 research universities that enroll the most international students reported significant declines in international graduate applications," he said. "Nine of these universities indicated a decrease of 30 percent or more. The number of international students enrolled at Purdue this fall is 4,921. That is down from 5,094 the year before. It is the first drop in international enrollment we have seen at Purdue in more than three decades."

Mr. Jischke says there are a number of reasons for the decline. Topping the list are tighter U.S. visa procedures, including a requirement that anyone seeking a student visa be interviewed in person by a U.S. consular official. Students often wait weeks for such interviews, which typically last just a few minutes.

Some institutions also report cases of foreign students or scholars in the United States being stranded abroad when they travel for academic conferences or home visits. Often these students find they have to renew their visas because of security clearances.

Delays in issuing visas mean that foreign students and professors are not able to arrive on time for the start of classes or to begin research projects on time.

But besides the restrictive visa procedures, there are other reasons for declining numbers of international students in the United States, according to educators.

Mr. Jischke of Purdue says other nations are marketing their colleges to foreign students and seeing an increase in applications. "American universities are facing significant increased competition for the top international students from institutions such as Great Britain, Australia, New Zealand, and Canada," he said. "The number of Chinese and Indian students going to universities in Australia last fall was up 25 percent. Great Britain saw a rise in Chinese and Indian students of 36 and 16 percent respectively."

Mr. Jischke is concerned about the impact the decline of foreign students in the United States will have if the trend continues. He fears it could hurt academic quality and U.S. competitiveness in fields from business to science and technology, as well as erode the U.S. standing in the world.

"The loss of these outstanding international scholars will not only be an economic blow to our country, I believe it also will work against our long-term interests to promote national security and improve international relations, friendships and understanding," he said.

Senator Norm Coleman, a Minnesota Republican, agrees. "We right now are losing that opportunity in massive numbers. I think this is a national security issue which will take its toll 20 years from now," he said. "But the seeds we fail to plant today, the seeds we are failing to plant today are going to have a direct impact on the ability that we have to work with other nations and other leaders who should be our friends and who should be schooled here."

Senator Coleman has introduced a bill that seeks to streamline the visa process for international students.

Meanwhile, the State Department has begun to expedite the student visa procedures by hiring more consular officers to handle interviews and updating technology to process applications.