WASHINGTON (JTA) -- U.S. House lawmakers want more answers after the Department of Justice reiterated the obstacles it says stand in the way of prosecuting alleged Palestinian terrorists who killed Americans.

Assistant Attorney General Ronald Welch in his April 5 letter was responding to a March 1 letter to U.S. Attorney General Eric Holder from Congress members that called on Holder to pursue prosecutions against Palestinian terrorists who were responsible for killing Americans and were recently released by Israel as part of the deal to free captive Israeli soldier Gilad Shalit.

The Welch letter, which was obtained by JTA, said “there are significant impediments to bringing prosecutions in the United States for attacks that occur overseas.” Welch echoed a statement that was sent in an email last month to the Parents Forum for Justice, a group of American citizens and parents whose children were killed or wounded by Palestinian terrorists in Israel.

“The crime scenes are located in places that are not under the United States’ control and, therefore, the United States is entirely dependent on the sovereign country where the attack occurred for assistance and cooperation in these investigations,” Welch wrote.

Reps. Joe Walsh (R-Ill.) and Howard Berman (D-Calif.), the ranking member of the House Foreign Affairs Committee, spearheaded the lawmakers' letter, which was signed by a bipartisan slate of 52 members of the House of Representatives.

In a statement to JTA, Berman noted that the “challenges of pursuing crimes in a foreign nation are clear,” but he was requesting further details from the Department of Justice.

“What remains unclear is whether Justice officials attempted to investigate or prosecute these individuals, and what their findings were," Berman said. "For instance, has the Justice Department reached out to Israeli authorities and sought to obtain evidence or relevant information regarding those individuals released by Israel with American blood on their hands? I look forward to further explanation from the Attorney General and his office."

Walsh said he was “disappointed" by the Department of Justice response "because I don’t hear the sense of urgency.”

“The impetus of our letter was that Justice has been negligent in not looking into some of these acts of terrorism overseas for quite some time,” Walsh said. “I think they’re beginning to get that message from a number of quarters, and I’m glad they responded, but there is huge concern that they are not going to follow up on what needs to be done.”

In 2005, Congress enacted the Koby Mandell Act, which was named for a 13-year-old Maryland boy who was stoned to death by Palestinian terrorists in 2001. The act created the Office of Justice for Victims of Overseas Terrorism to investigate and prosecute cases of terrorist attacks against American citizens overseas.

However, since the signing of the Oslo Accords in 1993, the Department of Justice has not prosecuted any of the 71 cases of Palestinian terrorist attacks against American citizens.

Sarah Stern, the president and founder of the Endowment for Middle East Truth, expressed her frustration with the Justice Department’s response to Walsh and Berman. Stern was involved early on in the effort to pass the Koby Mandell Act to establish the victims' office.

“This paltry response from the Department of Justice is absolutely revolting, and it’s a complete and total travesty of justice," she said in an interview with JTA.

Walsh indicated that he would work with Berman to respond to the Justice Department letter about courses of action in order to move through the "significant impediments" to the prosecutions.