Arizona Congressman Matt Salmon said the Marine veteran who has been in a Mexican prison on weapons charges after crossing the border is going well.

Salmon said he visited Sgt. Andrew Tahmooressi on Saturday at the Hongo II prison in Tijuana and the 25-year-old seemed in good spirits.

The congressman said he is confident Tahmooressi will be treated respectfully.

The Marine veteran was headed to San Ysidro, California, on March 31 when he mistakenly wound up at the border-crossing point in Tijuana with three legally owned guns in his trunk.

A petition on the White House website is asking President Barack Obama to demand Tahmooressi’s release. It has garnered more than 100,000 online signatures – the threshold that typically elicits an administration response.

“The effect of this unjust incarceration on a decorated combat Marine is despairing,” said the petition, which has more than 116,000 signatures.

Meanwhile, KTVK-TV reported, Tahomooressi's friends and family held a rally Saturday morning in Phoenix outside the offices of U.S. Senators John McCain and Jeff Flake.

They are asking lawmakers to help get Tahomooressi released.

The Associated Press contributed to this report.

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