WASHINGTON – The Justice Department will create an office devoted to capturing and prosecuting terrorists who kill Americans abroad, once legislation passed by both the House and the Senate is signed by President Bush.

The new office is intended to focus on Palestinian Arabs, its backers say.

The recently passed $388 billion spending bill includes the central plank of the Koby Mandell Act, named in honor of a 13-year-old Maryland boy who was killed by Palestinian Arab terrorists while hiking in Israel in 2001, where he had moved with his family five years earlier.

The legislation will establish an Office of Justice for Victims of Overseas Terrorism “to ensure that the investigation and prosecution of deaths of American citizens overseas are a high priority within the Department of Justice.”

The original Koby Mandell Act was conceived out of a concern that the American government under successive administrations was reluctant to prosecute Palestinian Arab terrorists for fear of upsetting diplomatic negotiations.

“The impetus for initiating this legislation was the conspicuous lack of action in capturing Palestinian Arabs who murdered 52 Americans since the Oslo Accords [of 1993],” said the president of the Zionist Organization of America, Morton Klein.

“To the best of knowledge, none have been captured, and they are walking as free men and women in the Palestinian territories,” said Mr. Klein, whose group has lobbied for the bill for three years.

The new legislation does not refer to Palestinians. Rather, it instructs the Justice Department to make sure that “all terrorists involved in such attacks are pursued, prosecuted, and punished with equal vigor, regardless of the terrorists’ country of origin or residence.”

Mr. Klein said he had received assurances from Senator Specter, a Republican of Pennsylvania who co-sponsored the Koby Mandell Act – and who successfully pushed for the amendment to be included in the appropriations bill – that Palestinian terrorists would be prosecuted.

“It is understood that the emphasis is on Palestinian nationals,” said Mr. Klein.

Mr. Specter was not available to comment yesterday.

In September, Mr. Specter, who is expected to take over the chairmanship of the Judiciary Committee, called the bill “vital legislation,” and said that combined with the Terrorist Prosecution Act it “gives our nation’s law enforcement officials the tools they need to arrest and prosecute terrorists who harm U.S. citizens abroad.”

Koby’s mother, Sherri Mandell, who lives in Israel, said the passage of the bill marks a “healing moment” for her family.

“We feel the U.S. is now with us in the fight against terrorism,” she said in a statement.

“We now feel that people care. We feel that Koby will not be forgotten and other Americans murdered by Palestinian terrorists will not be forgotten,” said Mrs. Mandell, who is a dual Israeli-American citizen.

The legislation also instructs the office to create a Joint Agency Task Force, consisting of Department of Justice and Department of State personnel, which would be activated in the event of a terrorist incident against American citizens overseas. The provision does not include the bluntly worded congressional findings of the original Koby Mandell Act, which stated that 100 American citizens have been murdered or maimed since 1968 in terrorist attacks in Israel and territories administered by Israel or the Palestinian authorities, and that the victims “have not received from the United States Government services equal to those received by other such victims of overseas terrorism.”

Those findings also said that “many terrorists” involved in the murders of Americans “are walking free there” and some have been given positions in the Palestinian Authority security forces, “and a number of schools, streets, and other public sites have been named in honor of terrorists who were involved in the murders of Americans.”

The congressional findings accused the American government of not advertising monetary rewards offered for the capture of suspected terrorists in areas administered by the Palestinian authorities.

Stephen Flatow, whose daughter Alisa, a 20-year-old student from New Jersey, was killed by a suicide bomber while studying in Israel in 1995, said the language in the appropriations bill had been “watered down” through compromise, but was a “good first step.”

“I don’t think America has really been focusing on some of the perpetrators of terror, especially as it concerns Israel. If anything, there has been a reluctance of the government to name names and point fingers,” he said.

A White House spokeswoman did not immediately respond to a request for comment yesterday.

The Senate has passed the appropriations bill, and the House version faces an additional vote to allow members to excise language that would have allowed members of Congress unprecedented access to private tax returns.