For years, many Islamic clerics have been arguing that the US's war on terror is a "holy war" against Islam. Now, those critics of US foreign policy have more ammunition to argue their point.

A Michigan supplier of sights for high-powered rifles has long been etching subtle references to Jesus on equipment it sells to the US military, possibly in contravention of army regulations that forbid religious proselytization.

Trijicon Inc., of Wixom, Michigan, describes itself as a company that "strives" to follow "biblical" morality, and the company is not shying away from its controversial and long-standing practice of enscribing references to New Testament passages on its rifle sights.

The news that Trijicon etches biblical quotes on its sights was first reported at the Accurate Shooter blog on Friday, and expanded upon by ABC News on Monday.

The company sponsors God's Great Outdoors, a radio ministry for Christian hunters on which the company's sales director, Tom Munson, has been interviewed. Trijicon's wordmark is listed as a "featured sponsor" on the radio show's Web site.

One rifle sight obtained by Accurate Shooter shows what appears to be a serial number that ends "JN8:12." That's a reference to John 8:12, which states, "When Jesus spoke again to the people, he said, ‘I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life.'”

Another rifle sight is encoded with "2COR4:6," which refers to Second Corinthians 4:6, a passage that states, "For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of God in the face of Jesus Christ."

Trijicon reportedly has a $660-million contract to provide rifle sights to the US Marine Corps, and a number of smaller contracts including a $33-million deal to provide machine gun sights to the Navy.

Trijicon's director of sales and marketing, Tom Munson, told ABC News that the inscriptions "have always been there" and do appear on weapons sold to the US military. Munson said there is nothing "wrong or illegal" with the practice of etching the Biblical passages on rifle sights, despite a ban on religious proselytization by US forces in Iraq and Afghanistan.

"US military rules specifically prohibit the proselytizing of any religion in Iraq or Afghanistan and were drawn up in order to prevent criticism that the US was embarked on a religious 'Crusade' in its war against al Qaeda and Iraqi insurgents," ABC News reports.

But many observers of the war in Iraq and Afghanistan say that proselytization by US forces happens anyway.

"It's wrong, it violates the Constitution, it violates a number of federal laws," Michael Weinstein of the Military Religious Freedom Foundation told ABC. "It allows the Mujahedeen, the Taliban, al Qaeda and the insurrectionists and jihadists to claim they're being shot by Jesus rifles."

Trijicon's Munson dismissed the concerns of Weinstein's group by saying it comes from a group that is "not Christian," ABC News reported.

"We believe that America is great when its people are good," the company states on its "about us" page. "This goodness has been based on biblical standards throughout our history and we will strive to follow those morals."

Many commenters on the Accurate Shooter blog took the company's side on the issue.

"I always consider whether my optics are manufactured by Christians or heathens," writes commenter Brandon. "Christians have a much better track record when it comes understanding and promoting the quality scientific research necessary to give us an edge on the battlefield than companies run by atheists."

"I am glad that the Bible references are there," writes commenter Alan Smithee. "If these people were right with Jesus, they wouldn’t see the need to drive airplanes into buildings and saw the heads off tourists!!!! ... We need to do our part (along with Israel). Thank God for Trijicon, and may we prevail in this epic battle!"