WASHINGTON - Nabila Mango, a therapist and a U.S. citizen who has lived in the country since 1965, had just flown in from Jordan in December when, she said, she was detained by U.S. Customs officers and her cell phone was taken from her purse. Her daughter, waiting for her outside San Francisco International Airport, tried repeatedly to call her during the hour and a half she was questioned. But after her phone was returned, Mango saw that records of her daughters' calls had been erased.

A few months earlier in the same airport, a tech engineer returning from a business trip to London objected when a federal agent asked him to type his password into his laptop computer. "This laptop doesn't belong to me," he said. "It belongs to my company." Eventually, he agreed to log on and stood by as the officer copied the Web sites he had visited, said the engineer, a U.S. citizen who spoke on the condition of anonymity for fear of calling attention to himself.

The seizure of electronics at U.S. borders has prompted protests from travelers who say they now weigh the risk of traveling with sensitive or personal information on their laptops, cameras or cell phones. In some cases, companies have altered their policies to require employees to safeguard corporate secrets by clearing laptop hard drives prior to international travel.

Today, the Electronic Frontier Foundation and Asian Law Caucus, two civil liberties groups in San Francisco, are filing a lawsuit to force the government to disclose its policies on border searches, including what rules govern the seizing and copying of the contents of electronic devices. They also want to know the boundaries for asking travelers about their political views, religious practices and other activities potentially protected by the First Amendment. The question of whether border agents have a right to search electronic devices without suspicion of a crime already is under review in the federal courts.

The lawsuit was inspired by some two dozen cases, 15 of which involved searches of cell phones, laptops, MP3 players and other electronics. Almost all involved travelers of Muslim, Middle Eastern or South Asian background, many of whom, including Mango and the tech engineer, said they are concerned they were singled out because of racial or religious profiling.

A U.S. Customs and Border Protection spokeswoman, Lynn Hollinger, said customs officers do not engage in racial profiling "in any way, shape or form." She said a laptop may be seized if it contains information possibly tied to terrorism, narcotics smuggling, child pornography or other criminal activity.

The Association of Corporate Travel Executives, which represents 2,500 business executives in the United States and abroad, said it has tracked complaints from several members whose laptops have been seized and their contents copied before usually being returned days later.

The U.S. government has argued in a pending court case that its authority to protect the country's border extends to looking at information stored inside electronic devices. In border searches, it regards a laptop as no different from a suitcase.

As more and more people travel with laptops and BlackBerrys and cell phones, the government's laptop-equals-suitcase position is raising red flags.

"It's one thing to say it's reasonable for government agents to open your luggage," said David Cole, a law professor at Georgetown University. "It's another thing to say it's reasonable for them to read your mind and everything you have thought over the last year."