Two Harvard Law School students have sued the Transportation Security Administration, seeking to restrict the use of full-body scanners and pat-downs at airports and joining a growing number of lawsuits filed across the country that claim the screening procedures infringe on constitutional rights to privacy.

The body scans, which show images of airline passengers’ naked bodies, and the pat-downs, which include touching groin areas, violate the Fourth Amendment, which prohibits unreasonable searches and seizures, according to the complaint filed Monday in US District Court in Boston. The students, Jeffrey Redfern and Anant Pradhan, are asking the court to ban the TSA from using the screening procedures without reasonable suspicion.

Margaret Paget, a partner at the Boston law firm Sherin and Lodgen, said the Harvard students, who are representing themselves in the suit, have a valid claim and a chance of winning.

“We all expected this case was going to be brought by the ACLU,’’ she said. “There’s a widespread public concern over the scope and extent of the searches.’’

The suit is at least the sixth filed against the TSA since the agency put the enhanced screening procedures into widespread use following the so-called underwear bomber’s unsuccessful attempt to blow up a plane last Christmas with explosives hidden beneath his clothes. A suit filed in US District Court in Denver last week claimed the pat-downs were “disgusting, unconscionable, sexual in nature.’’ The Electronic Privacy Information Center, an advocacy group, described the scanners as the equivalent of a “digital strip search’’ in a suit filed in Washington in July.

“I see the lawsuits as part of a genuine citizen rebellion against invasive and ineffective airport screening,’’ said John Verdi, senior counsel at the privacy information center. “These scanners fail every conceivable constitutional test. They are not narrowly targeted at individuals that the government suspects of wrongdoing. They are not the least invasive means. And they are not effective at achieving the government’s stated end, which is detecting powdered explosives.’’

A TSA spokeswoman declined to comment on the lawsuits. The agency, however, is working with technology companies to develop software that would show a generic paper-doll-like figure instead of an actual image of a passenger’s body.

Under TSA screening procedures, passengers selected for full-body scans can opt for a pat-down search instead. Redfern and Pradhan both chose the pat-down at Logan International Airport while traveling separately in November, according to their complaint. The search, which included “prodding and lifting of genitals and buttocks,’’ was so intrusive that, “if done non-consensually, would amount to sexual assault in most jurisdictions,’’ the complaint said.

In an interview with the Harvard Law Record, Pradhan said an agent put his fingers inside the waistband of his pants, lifted his buttocks, and felt his groin. “They’ll go all the way up until — well, they go all the way up,’’ he told the law school newspaper.

Pradhan and Redfern declined to comment yesterday.

Most passengers are still screened by traditional metal detectors. But complaints about the revealing full-body scans and aggressive pat-downs by TSA officers grew to a national controversy as the holiday traveling season kicked off last week. The dissatisfaction over the these screening methods sparked a protest on the day before Thanksgiving, one of the busiest travel days of the year. A loosely organized group urged travelers to opt for more time consuming pat-downs to draw attention to privacy concerns. The protest generated widespread media coverage, but didn’t cause disruptions at airports.

Katie Johnston Chase can be reached at johnstonchase@globe.com.

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