LONDON, (AP) – President Bush is sending his national security adviser to the Middle East next week and Secretary of State Condoleezza Rice will make a return visit soon afterward to keep up pressure on Israeli and the Palestinians to start peace negotiations.

National security adviser Stephen Hadley and Rice will make separate trips to the region to bridge wide gaps between the two sides on a document outlining how they intend to resume talks that will be presented at a U.S.-hosted conference this fall, a senior official said.

The announcement came as Rice said she was encouraged by what she had heard during four days of intense meetings with Israeli and Palestinian officials and civic and business leaders in Jerusalem, and Ramallah and Bethlehem in the West Bank.

But Rice also acknowledged splits between the two sides as they try to craft a joint statement that is to be endorsed at the conference in late November or December at Annapolis, Md., which the United States hopes will relaunch negotiations to create a Palestinian state.

“I think they are very serious,” Rice told reporters Thursday as she flew to London after completing her seventh trip to the Middle East this year. “The teams are serious. The people are serious. The issues are serious.

“So I am not surprised that there are tensions, I am not surprised that there are some ups and downs,” she said. “That is the character of this kind of endeavor, but I was encouraged by what I heard.”

Hadley’s trip, so close on the heels of Rice’s visit this week, is intended not only to move the two sides closer but to underscore the U.S. commitment to the creation of a Palestinian state, the official said. Rice will then return in late October or in early November.

Rice’s trip will also take her to an Iraq neighbors meeting in Istanbul, Turkey, said the official, who spoke on condition of anonymity because neither the Hadley trip nor Rice’s return visit have been formally announced. The official did not give specific dates for the travel.

The flurry of diplomatic activity aims to push Israel and the Palestinians into consensus on the substance of the conference’s joint declaration, which would outline a way for the two sides to return to the negotiating table after seven years of bloodshed and diplomatic paralysis.

The Palestinians and their Arab allies such as Egypt and Jordan are insisting the document be detailed and specific with a timetable for formal peace talks, and the Israelis want language that is more vague.

Rice, who won public backing for the conference from Egypt during a Tuesday stop in Cairo, was in London on Thursday to lobby for backing from Jordan’s King Abdullah II. The two had a private lunch.

Rice had downplayed the chances for any breakthroughs this week but appeared pleased with the results of the mission even as she continued to warn that difficult work is still ahead.

Many of her discussions focused on the security and economic issues that will present themselves once a Palestinian state is created side-by-side with Israel.

“I am quite convinced that one of the really crucial pieces that has to be filled in are these concepts of how the states will relate to each other in practical terms concerning security and in practical terms concerning economic issues,” she said.

Rice also stressed that the joint statement will only be a starting point for formal peace talks and will not be intended to resolve those issues.

“All this document is trying to do is to demonstrate that they now believe they have a basis for pushing forward on the resolution of those outstanding issues,” Rice said.

The Palestinians want the document to include at least a sentence or two on how to solve each of the major issues of dispute, such as borders and Jerusalem, which both sides want to claim as their capital.

The Palestinians’ core demand is that the future border between Israel and Palestine be based on the pre-1967 Mideast War lines, with modifications through land swaps. Israel captured the West Bank and other areas in the 1967 war.

But Israel has balked at such specificity and the Palestinian president Mahmoud Abbas angrily complained when Rice tried to get him to back down, according to a senior Palestinian official.

Israel is “hindering the endeavor to reach a document with substance,” Abbas said. His comments drew a rebuke from Israeli Foreign Minister Tzipi Livni who said she would not stoop to play “the blame game.”