Bishop Stephen Blaire of Stockton, Calif. and leaders of several major Catholic organizations urged a better response to the "crisis" of gun violence, including criminal background checks on all gun buyers.

"In light of the tragedy in Newtown – and in Aurora, Tucson, Fort Hood, Virginia Tech, Columbine, Oak Creek, and so many more – we know that no more time can be wasted," read the letter to Congress members from the D.C.-based interfaith organization Faiths United to Prevent Gun Violence.

"Gun violence is taking an unacceptable toll on our society, in mass killings and in the constant day-to-day of senseless death."

The Jan. 15 statement also urges a ban on high-capacity weapons and ammunition magazines, and federal laws against gun trafficking.

"While we continue to pray for the families and friends of those who died, we must also support our prayers with action," the letter said. "We should do everything possible to keep guns out of the hands of people who may harm themselves or others."

Bishop Blaire signed the letter in his capacity as chairman of the U.S. bishops' Committee on Domestic Justice and Human Development.

Other Catholic signatories include Father Larry Snyder, CEO of Catholic Charities USA; Sister Carol Keehan, D.C., President and CEO of the Catholic Health Association; Sr. Janet Mock, C.S.J., Executive Director of the Leadership Conference of Women Religious; and Very Rev. John Edmunds, S.T., President of the Conference of Major Superiors of Men.

The letter comes in the wake of the Dec. 14 shootings at Sandy Hook Elementary School in Newtown, Conn. where a 20-year-old man shot and killed twenty children and six adults before killing himself.

"We should do everything possible to keep guns out of the hands of people who may harm
themselves or others," the letter said. "We should not allow firepower to kill large numbers of people in seconds anywhere in our civil society. And we should ensure that law enforcement has the tools it needs to stop the virtually unrestrained trafficking of guns."

Faiths United to Prevent Gun Violence advocates legislation requiring national background checks for all gun sales, including online sales, gun show sales and private sales.

The group said high-capacity weapons and ammunition magazines have "no legitimate self-defense or sporting purpose" and are "the weapons of choice for those who want to shoot and kill a large amount of people quickly." The group said the federal assault weapons ban that expired in 2004 should be used as a basis for an updated law against the weapons.

The group said federal laws against gun trafficking are needed because prosecutions take place only under a law that bars the sale of guns without a federal license.

Other signatories to the group's letter include leaders from the Dominican Sisters of Peace, the Franciscan Action Network and the Sisters of Mercy of the Americas. Many Protestant, Jewish, Muslim and Hindu leaders also signed the letter.

There were 12,664 murders in the U.S. in 2011, according to incomplete crime statistics reported to the FBI. Of these, 8,583, about 68 percent, were committed with firearms.

Improved medical treatment in recent decades has caused a decrease in homicide victims, as survivors of gun violence are now classified as victims of aggravated assault, the Wall Street Journal reported in December. Firearms were used in 21 percent of the 703,975 aggravated assaults the FBI recorded for 2011.

Bishop Blaire has previously spoken about the need to address gun policy. In a Dec. 21 statement, he joined Bishop John C. Wester of Salt Lake City, chair of the U.S. bishops' Communications Committee, and Bishop Kevin C. Rhoades of Fort Wayne-South Bend, chair of the U.S. bishops' Laity, Marriage, Family Life and Youth Committee, calling for cultural changes and policy study in the wake of the Newtown shooting.

They urged that national leaders reconsider firearm policies, mental health treatment ability, and violence in the entertainment industry. They also advised broader efforts to restore the value of human life in society.