SEATTLE, Washington (CNN) -- The FBI wants to question two men who were described as behaving oddly on a Washington state ferry earlier this summer.

The FBI wants to speak with these two men seen on a ferry in Washington state earlier this summer.

Members of the public and ferry workers reported the men to authorities after the two were seen pacing in areas of the boat, including a cargo hold, as if trying to measure distances, FBI Special Agent Larry Carr said Tuesday.

The men were also seen about two months ago taking photographs of the ferries -- including restricted areas -- and studying an emergency evacuation poster.

The men were spotted on multiple ferries and ferry routes, Carr said.

The FBI wants to question the men to determine if their behavior was harmless or whether they were surveilling the ferries and ferry terminals for nefarious purposes.

A ferry worker snapped photos of the men using a cell phone camera and gave the stills to law enforcement. The photos were shown to police and ferry workers, but no one could identify the men, so authorities called on the public for help.

Pictures of the men have appeared in media outlets for more than a week. None of the 200 tips that have come in so far has led investigators to the men.

Some news organizations have refused to publish the photos, saying the men have not been accused of a crime. It appears the men could be of Middle Eastern origin.

Although the initial FBI news release on the men did not discuss their possible ethnicity, "We just want to ensure that there is just one standard being implemented for suspicious behavior for both people who appear to be Middle Eastern and those who appear not to be Middle Eastern," said Naseem Tuffaha of the American-Arab Anti-Discrimination Committee.

Carr said the FBI made the photos public because "the result of not doing anything at that point in time is a ferry blowing up and thousands of people losing their lives. We can't let that happen."

More than 25,000 people commute daily through the Seattle Ferry Terminal and more than 9 million people travel through the terminal annually, according to the Washington State Department of Transportation web site.

But various FBI officials have stressed the agency is acting out of an abundance of caution and that the men seen on the ferry could have a logical and harmless explanation for what they were doing.

Robbie Burroughs, also with the FBI in Seattle, said the ferry system could be an attractive target to terrorists.

"Here the ferries are the equivalent of subways, so we are cautious," Burroughs said last week when the effort to identify the men began.

Since the September 11, 2001, terrorist attacks, U.S. law enforcement has emphasized the need for the public to report suspicious behavior.

Many such reports turn out to be nothing of concern.

However, seizures of al Qaeda materials overseas have turned up reconnaissance photos taken in the United States. E-mail to a friend

CNN Homeland Security correspondent Jeanne Meserve and senior producer Carol Cratty contributed to this report.

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