Catholics from a range of influential posts -- former U.S. ambassadors, national representatives of theologians, sisters and more -- called Wednesday for new gun control measures, naming Catholic members of Congress seen as roadblocks to tighter regulations.

The 64 Catholics among those signing the letter, released by nonprofit group Faith in Public Life, call on people who consider themselves pro-life to support new gun control measures, saying people "who share a firm commitment to these values" have "no excuse for inaction."

Among the signers are Miguel Diaz, until recently U.S. Ambassador to the Holy See, and Thomas Melady, who held that post under President George H.W. Bush.

The signers asked Catholic members of Congress -- including Republicans House Speaker John Boehner and Congressman Paul Ryan and Democratic Senators Joe Donnelly and Heidi Heitkamp -- to "stand up to the National Rifle Association and other gun lobbyists who choose to obstruct sensible reforms."

"We urge you to reflect on the wisdom in our church's call for a 'consistent ethic of life' as you consider legislation in the coming months that can provide greater protection for our families and communities," the letter states.

Those who signed the letter include Franciscan Sr. Florence Deacon, the president of the Leadership Conference of Women Religious; Francis Doyle, a former associate general secretary of the U.S. bishops' conference; and Marie Dennis, co-president of Pax Christi International.

Also included is the leadership team of the Sisters of Mercy of the Americas, one of the largest groups of Catholic sisters in the western hemisphere, and leaders of both the College Theology Society and the Catholic Theological Society of America.

Wednesday's letter comes a week after a similar letter calling for new gun control measures garnered the signatures of the leaders of the Catholic Health Association, the Conference of Major Superiors of Men, and Stockton, Calif., Bishop Stephen Blaire, chairman of the U.S. bishops' Committee on Domestic Justice and Human Development.

Mentioning statements from the U.S. bishops and the Vatican calling for more stringent gun control measures, the 64 signers conclude: "The complexity of this urgent challenge must not be an excuse for protecting the status quo when it comes to regulating the sale and use of lethal weapons."

"President Obama and Members of Congress can honor the memories of those killed in Newtown, Conn., and work to prevent future tragedies by acting now."