WASHINGTON — Congressional leaders will release a letter today to the Chinese government pleading with Beijing to protect persecuted North Koreans fleeing their country for food and the right to practice Christianity.

The lawmakers are spurred in part by the latest report from the U.S. Commission on International Religious Freedom: “A Prison Without Bars.” The report is based on detailed accounts from former North Korean security agents and refugees on how Kim Jong Il’s regime executed, tortured, and interrogated its countrymen for the crime of seeking refuge in churches.

The report details how many women fleeing North Korea are sold to the Chinese mafia into sexual slavery. One defector said she saw a 20-year-old woman sold to a 70-year-old man as a bride.

For those refugees who are not sold into slavery, the fate in detention centers is worse. Some victims are forced to stay for months in these facilities and endure beatings and meals consisting of three small mouthfuls of cornmeal, beans, and rice. The well-behaved are allowed to fill their stomachs with a watery soup.

The most shocking disclosures come from the prison guards and interrogators themselves. One man describes the job of the baekjeong, or man-butcher. These are operatives trained in killing people with one blow of a hammer to the back of the head. One former security officer describes such an execution: “The [accused] digs the hole to be buried and then the baekjeong strikes him just one time with a two-knuckle-sized hammer.”

In response to these new details, Senator Brownback, a Republican from Kansas, and Rep. Frank Wolf, a Republican from Virginia, are circulating a letter in Congress asking the Chinese president, Hu Jintao, to end his country’s policy of repatriating North Korean refugees to these detention centers ahead of the summer’s Olympic Games in Beijing.

“We urge you to end your policy of repatriating the North Korean refugees to North Korea where they face punishment, torture and sometimes execution for leaving their homeland,” a draft of the letter says.

President Bush yesterday also issued a personal statement regarding the refugees. “I am deeply concerned about the grave human rights conditions in North Korea, especially the denial of universal freedoms of speech, press, religion, assembly, and association, and restrictions on freedom of movement and workers’ rights,” Mr. Bush said, commemorating North Korea Freedom Week, the president said, “I am deeply concerned by the stories of divided families, harsh conditions, and suffering. The United States stands with the North Korean people in their call for freedom. We believe it is every person’s basic right to live in freedom and dignity. We will continue to support the North Korean people as they strive to achieve the rights and freedoms to which they are entitled as human beings.”

A spokesman for the New York City Philharmonic Orchestra, which traveled earlier this year to Pyongyang to perform, yesterday had no comment on the report of the U.S. Commission on International Religious Freedom.

Thus far, President Bush has resisted the commission’s recommendation to incorporate human rights into the six-party nuclear non-proliferation talks with North Korea, a negotiation that until last week the White House touted as a foreign policy success.

In January, the president’s envoy for human rights in North Korea, Jay Lefkowitz, delivered a speech at the American Enterprise Institute warning against a deal with North Korea and making the case that human rights conditions in North Korea have not improved after nearly three years of the multi-national diplomacy.

At the time, the State Department said Mr. Lefkowitz did not speak for the administration. Two Bush administration officials yesterday said Mr. Lefkowitz, a senior domestic policy adviser in the president’s first term, has been sidelined since giving his speech.

A draft of the North Korea Human Right Act, under consideration by the House Foreign Relations Committee, would make the position of special envoy for Human Rights in North Korea a full time position. Mr. Lefkowitz works only on a part time basis.

One of the religious freedom commissioners, Nina Shea, who is also a scholar at the Hudson Institute, said, “I think the time now is for the United States to introduce human rights, particularly religious freedom, which is at the core of the repression in North Korea, into its negotiations with North Korea.”

Mr. Brownback, Mr. Wolf and members of the U.S. Commission on International Religious Freedom will give a press conference today to discuss the report.