The Bush administration is negotiating with Israel over whether its settlements in the West Bank can grow within existing settlement boundaries, Secretary of State Colin L. Powell said yesterday.

The U.S.-backed peace plan known as the "road map" calls on Israel to freeze "settlement activity," including what is known as "natural growth," or construction because of births and marriages. The Israelis have never accepted that definition and have long pressed the Bush administration to allow growth within what are called existing "construction lines." U.S. officials have quietly discussed ways to accommodate Israeli concerns, but in public statements they have insisted that a freeze on settlement growth means a freeze.

In an interview with Egyptian television, however, Powell said: "We are concerned about all kinds of settlement activity, to include different definitions of what growth is. And we're working with the Israelis to define what a settlement is and what the difference is between natural growth and expansion, and is natural growth something that is consistent with the Israelis' commitments to us."

Israeli officials and some administration officials said Powell's statement appears to be the first official acknowledgment that the United States is prepared to adopt a more flexible definition of a freeze as sought by Israel.

A senior State Department official, after checking with Powell, said Powell did not mean to suggest a new policy. "The policy is to have an end to settlement activity," the department official said. "The Israelis have some ideas about what that means," but the administration wants to make sure Israeli actions on settlements are "consistent with the commitments they made to us."

Yet the administration's statements have undergone an evolution in recent months, especially as Israeli Prime Minister Ariel Sharon battled for his plan to unilaterally withdraw from settlements in the Gaza Strip. The Israeli Knesset approved the plan this week.

At a briefing on Aug. 18, when asked if natural growth of settlements was open to interpretation, spokesman J. Adam Ereli said: "I don't have anything for you on that."

But last month, also during an interview with Egyptian television, Deputy Secretary of State Richard L. Armitage mused openly about a definition of natural growth. "If you have settlements that already exist and you put more people into them but don't expand the physical, sort of, the area -- that might be one thing," he said. "But if the physical area expands and encroaches, and it takes more of Palestinian land, well, this is another."

In fact, some key administration officials, such as Elliott Abrams, the top Middle East specialist on the White House's National Security Council staff, privately have long pressed for a more expansive definition of natural growth.

After Sharon announced his plan to withdraw from Gaza last December, a senior administration official told reporters at a briefing that the purpose of a settlement freeze is to make sure additional settlers would not impede Palestinian life or prevent the formation of a viable Palestinian state. It makes no difference, he said, if the Israelis add another house within a block of existing homes. "We have not taken the position there has to be an end to natural growth in settlements," he said.

In April, President Bush said that Israel could expect to retain some West Bank settlements in a final peace deal because of "new realities on the ground." In a letter to national security adviser Condoleezza Rice at the time, a top Israeli aide to Sharon committed to quickly seeking restrictions on settlement growth, including having U.S. and Israeli officials "jointly define the construction line of each of the settlements."

A technical team of U.S. experts was scheduled to visit Israel to review the Israeli proposals several months ago, but the trip was postponed.

Officials familiar with the discussions said it has been difficult to draw such lines, in part because synagogues are sometimes placed far from housing in settlements. When the synagogue is included, in some cases the construction line would allow significant expansion within a settlement.