The Mexican attorney general's office has defended its treatment and handling of Sgt. Andrew Tahmooressi, a Marine reservist who was arrested April 1 and since held in Mexican prison after accidentally crossing the border in San Ysidro with his registered firearms in the back of his pickup truck.

The Marine, who is being held on weapons charges, was initially kept in La Mesa prison near Tijuana where he claimed he was being mistreated and "tortured." Tahmooressi has been transferred to the El Hongo prison outside of Tecate, where his supporters have said conditions are better, The Los Angeles Times reported.

Amid mounting pressure from U.S. officials calling for Tahmooressi's release, the attorney general's office released a statement insisting that the 25-year-old's claims are "baseless." It added that it "reiterates its commitment to the observance of human rights and respect for due process of all arrested."

"From the moment of his arrest, Mr. Tahmooressi's fundamental rights have been respected, including the rights to due process and personal integrity, as well as his right to consular notification and access, given that he is a foreign citizen," according to the statement.

Tahmooressi's court hearing was canceled after he fired his Mexican lawyer and no date has been rescheduled, The Times reported.

Two-dozen Congressional members along with veterans groups have come to Tahmorressi's aid and called for his release. The Marine, who served two tours in Afghanistan, has received visits from a pastor and Rep. Matt Salmon (R-Ariz.).

The commander in chief of the Veterans of Foreign Wars of the U.S. wrote a letter to President Barack Obama this week urging him to get involved. The commander asked Obama to "show the same sense of urgency toward Tahmorressi as you did to secure the release of "Army Sgt. Bowe Bergdahl, who was held in Afghanistan by the Taliban for five years.

Tahmooressi told reporters that he had moved from Florida to San Diego where he was hoping to undergo post-traumatic stress disorder treatment at the Veterans Affairs hospital in La Jolla. He said he got lost traveling along Interstate 5 and ended up in Mexico.

"In Mexico, as in the U.S., ignorance of the law, error or misunderstandings about the consequences of breaking the law, do not exempt an individuals from responsibility, according to attorney general's statement.

Tahmooressi was traveling with a rife, a shotgun and a .45-caliber pistol as well as several rounds of ammunition, which is legal in the U.S. but illegal in Mexico, according to The Times.

Mexican officials said that Tahmooressi "demonstrated violent behavior, twice attempting to escape," during his time at the La Mesa prison. But Tahmooressi insisted that he was tortured and had to fight back to protect himself.