(CNN) -- The mothers of U.S. hikers held by Iran said a magazine article that contradicts government claims they crossed the border before their arrests is "concerning" and raises many questions.

The article written for the July 12 edition of The Nation cites two witnesses who said they saw members of Iran's national police force cross the border into northern Iraq to apprehend Shane Bauer, Sarah Shourd and Josh Fattal.

"The witnesses, who followed the Western-looking hikers out of curiosity, say that around 2 p.m. on July 31 (2009), as the hikers descended the mountain, uniformed guards from NAJA, Iran's national police force, waved the hikers toward the Iranian side using 'threatening' and 'menacing' gestures," the article says.

"When their calls were ignored, one officer fired a round into the air. As the hikers continued to hesitate, the guards walked a few yards into Iraqi territory, where they lack jurisdiction, and apprehended them," according to the article.

Bauer has previously denied government claims that the hikers crossed into Iranian territory.

The Nation: U.S. hikers were seized in Iraq

The witnesses are residents of a Kurdish village in northern Iraq called Zalem, according to the story written by Babak Sarfaraz, a pseudonym for a journalist in Iran. Since the community lies a few miles from the Iranian border, they asked not to be identified, fearing retaliation from Iranian forces, the article said.

The magazine said its reporting was based on a five-month investigation. CNN could not independently confirm the story and a senior State Department official said the agency can't corroborate the report.

"It was very concerning for me to see the details of this," Cindy Hickey, Bauer's mother, told CNN. "It sends a shudder down my spine."

"All of this is still mysterious," said Nora Shourd. "This raises a lot of questions for us."

The three Americans have been held for nearly a year. Their mothers visited them in Iran in May.

Last week, the women said the Iranian government should either prosecute or free the three.

In a statement, the mothers also called for more consular access for their children and for them to be able to call their families.

They also asked that Shourd be moved from solitary confinement.

"Shane, Sarah and Josh have been detained in Iran without due process for almost 11 months, in continued violation of Iranian and international law," the mothers said.

"To continue to detain our children without regard for their legal and human rights reinforces suspicions that they are being held in a cynical attempt by Iran to exert leverage with the United States. Iran has no legitimate reason at this stage not to release them or move forward with a fair trial in which our children can openly answer any allegations against them."

CNN's Susan Candiotti, Ross Levitt and Elise Labott contributed to this report.