His friends warned him not to leave the U.S., but the heart surgery of his father, the death of his grandmother and his possible marriage called him home.

That was three months ago. Now, Seyed Safa Eslambolchi, a 29-year-old Iranian Penn State student (graduate-civil engineering), continues to wait for a reply from the U.S. consulate about a return Visa -- an answer that was supposed to have only taken four weeks.

In the meantime, he risks losing his graduate assistantship, and until a few weeks ago, was still paying for a State College apartment, where his furniture and many of his belongings remained.

Penn State International Student Services (ISS) has seen increased security checks, Negar Davis, director of ISS, said.

"Sometimes names trigger security and clearance checks, or particular majors that students are pursuing that are sensitive and have to do with national security," she said.

Eslambolchi's major, civil engineering, is one of many science and technology courses of study deemed sensitive on the Technology Alert List of the U.S. Department of State.

Eslambolchi is from a "state sponsor of terrorism," according to a section of the Enhanced Border Security and Visa Reform Act of 2002. All applicants 16 and older from North Korea, Cuba, Syria, Sudan or Iran must fill out a DS-157, or a Supplemental Nonimmigrant VISA Application, and appear before a consular officer to secure a Visa needed to enter the U.S.

If the applicant passes the interview, the consulate sends the case to Washington, D.C., for background checks by the FBI and other clearing agencies, said Eslambolchi, who first came to the U.S. from Tehran, Iran, in fall 2005.

"They give us a single entry Visa, which is valid for two to three months in order to get into the United States," he said. "And every time you want to leave the United States, you have to apply for a new Visa."

Turning away international students is not the intent of the U.S., said Steve Royster, spokesman for the Bureau of Consular Affairs of the U.S. Department of State.

"You have to recognize that 90 percent of Visas are issued within two days, when the decision is favorable," he said.

Royster said in the case of a student visiting from a "state sponsor of terrorism," the Visa issuance process is done on a case-by-case basis. He added there are simply statutory requirements.

"A real benchmark of our approach toward international travel is secure borders, open doors, and the first part of that is secure borders," he said. "In the era we live in, we have to satisfy ourselves of any security concerns, in conjunction with allowing people in."

Jhanvi Dangaria (graduate-bioengineering), a student from India, said another student from her same project, in the same lab and same department, went home the same time she did. The student went to a different consulate and didn't get checked, while Dangaria did -- resulting in a seven-week wait.

The long delay faced by Eslambolchi is possibly a result of some clerical mess-up, Davis said.

Yi Liu (graduate-integrative biosciences) faced a similar situation after returning home to see her parents in Wuhan, China, in winter 2005.

"At that time, I was checked, because my major was somewhat sensitive," she said. "Plant biology. I'm not studying pharmaceutical. I don't think plants can be dangerous, I don't know."

Liu said U.S. officials asked to see her Penn State adviser's résumé, which she had to download from his home page. After two months of waiting, she was allowed to return -- a month late for spring classes.

"This experience gave me such a hard time that I don't want to take the risk to go back to China again, although I miss my parents and friends there so much," Liu said.

While other students return to their lives, Eslambolchi, who is employed as a translator in Iran, said he waits and wonders.

"I understand and respect the procedure," Eslambolchi said, "but I do expect them to understand my situation -- that I have been missing my classes and this semester."

Both Eslambolchi and Davis said they would like to see an online tracking system where people can be looked at more quickly and efficiently to make it back to their livelihoods and research.

"At least if I could check online to see in what stage it is and how long it would take. If they could have a rough estimate on it, I could at least plan for my life," Eslambolchi said.

Davis said she and other international education advocates try to change the negative impression many get from the U.S. that it is not a welcoming environment.

"Behind every case is a human being expecting some sort of resolution delivered in a timely fashion," she said.