As the federal government increases the identification requirements for American citizens traveling abroad, the line outside the passport office on Hudson Street in Manhattan grows.

“We may be in this line until Friday,” Margaret Hoffman said as she stood yesterday with her daughter, Jane Sternbach, who is waiting for a passport for a trip to London.

At 2 p.m. the 50-person-long line at the agency spilled outside onto the sidewalk and turned the corner onto King Street. There were plenty of complaints, but few people seemed surprised. Anticipating the wait, some had come with umbrellas to open against the sun in yesterday’s sweltering heat.

The State Department is on track to issue more than 17 million passports this year, a department spokesman, Steve Royster said. In 2006, the department issued slightly more than 12 million.

But that increase hasn’t kept up with demand. While a wait of between four and six weeks was once customary for a passport, Ms. Sternbach applied for her passport more than three months ago. Her wait isn’t so unusual these days. At the last count, conducted earlier this month, the State Department had about 500,000 applications that had been pending for at least 12 weeks, Mr. Royster said.

The backlog is partly due to a law that will require Americans to present a passport upon returning from Canada, Mexico, and other nearby countries. Previously a driver’s license accompanied by a declaration of American citizenship was the norm. The law had gone into effect for air travelers, but the Department of Homeland Security postponed enforcement this month because of the backlog from the sudden rush in passport applications.

The law was to go into effect for land and sea travelers beginning next January, but the secretary of homeland security, Michael Chertoff, postponed that, too, this month, according to news reports.

The State Department is taking steps to clear the line at its door.

The call center’s hours are kept open past the usual 6 p.m. closing, until midnight. It has created a task force of 350 additional employees to assist in passport matters. A passport printing press in Hot Springs, Ark., is in its test phase, although it may eventually roll out 10 million passports a year. The department is issuing a record number of passports a month, some 1.5 million.

But the best way to clear the lines, Mr. Royster suggested, would be for people to stay at home and press for their passports through the telephone and mail.

“While we understand the frustration of people,” he said, “that’s not a cause to come to the agency.”

The agency still expedites passports on an emergency basis.

“If you showed up at JFK for your trip to Uzbekistan and suddenly realized your passport had expired, one might think you were out of luck, but that is not so,” Mr. Royster said. “You would hop into a taxi, and get to a passport station. On that emergency basis, we would try to process a passport to you in the next day or possibly that day.”

Meanwhile, new requirements announced this week will soon require foreign travelers to America to give digital scans of all 10 fingerprints. A homeland security spokesperson said the new system could be operational in several airports, including John F. Kennedy International Airport, by as early as October. The State Department is currently using 10-fingerprint scans on visa applicants in 28 countries abroad.

Since 2004, America has requested two fingerprints from visitors. From those prints, the homeland security department has amassed a print database of about 90 million different visitors, a department spokeswoman, Anna Hinken, said.

Ms. Hinken ascribed two advantages to a 10-fingerprint system over the current one. It will be faster in searching for matches with past prints entered into the system, lowering wait time at airports, she said. Also, it will allow border guards to match visitors against a wider set of prints.

“We’ve been collecting fingerprints from all over the world,” Ms. Hinken said. “The Department of Defense shares fingerprints it finds from caves in Afghanistan.”

In the past, America’s fingerprinting requirements have drawn mild resentment from other countries, especially Brazil. Nations belonging to the European Union are now in the process of setting up a fingerprinting system as well, according to news reports.