U.S. and Iraqi negotiators have agreed on a draft security pact that would govern the presence of American troops in Iraq after January, Bush administration officials say, but its final approval is far from certain.

The draft calls for U.S. troops to pull out of Iraqi cities by the end of June next year and leave Iraq by Dec. 31, 2011, unless the Baghdad government asks them to stay. It also includes a compromise on the biggest bone of contention: legal immunity for American forces, according to the officials, who spoke on condition of anonymity to discuss the evolving diplomacy on the so-called Status of Forces Agreement.

The draft, reached after months of halting and often tense talks, contains elements that are expected to further aggravate an already difficult effort to get the Iraqi government and parliament on board, the officials said.

It also may draw objections from U.S. lawmakers, whose support is not legally required but is considered essential to the eventual success of any deal, according to the officials.

However, the negotiating teams have decided they cannot improve on the proposal and have sent it to higher-ups for a political decision as time runs out on both the Bush administration and the U.N. mandate under which U.S. troops now operate, which expires on Dec. 31, they say.

Without an agreement soon, the officials said Tuesday that the two sides will have to begin look more seriously at alternatives that include extending the U.N. authority, which is fraught with complications.

The officials would not discuss the draft agreement in detail. Yet they did discuss the troop pullout dates and described in general outlines the provisions on legal immunity. Under the agreement, Iraqi authorities would have a limited role in the prosecution of off-duty U.S. soldiers accused of committing crimes off their bases, they said.

Meanwhile, civilian employees of the Defense Department would be afforded the same immunities granted to State Department workers under the Vienna Convention on Diplomatic Relations, the officials said.

The compromise allows Iraq to claim jurisdiction over Americans while preserving nearly all the protections U.S. forces and employees now hold in Iraq. The vagueness appears deliberate, thus allowing both sides to argue they got concessions they needed.

A military official said top Pentagon leaders are not entirely happy with the legal immunity compromise as written in the draft. Officials have said repeatedly, however, that the administration "can live with" the proposed deal.

Officials said Secretary of State Condoleezza Rice and other top Bush aides will soon to begin briefing key members of Congress on the draft, some of whom they fear will oppose the immunity provisions.

But of greater concern, U.S. officials fear that Iraqi Prime Minister Nouri al-Maliki may not be able to sell it to either his own government or the Iraqi parliament.

There is intense opposition to any surrender of Iraqi sovereignty among al-Maliki's Cabinet and lawmakers.

On Tuesday, in Baghdad, al-Maliki presented the tentative accord to President Jalal Talabani as well as to the country's Sunni and Shiite vice presidents. They were the first in a series of sessions aimed at measuring political support for the agreement in Iraq.

An official statement said al-Maliki, Talabani and the two vice presidents — Tarik al-Hashemi and Adil Abdul-Mahdi — studied the draft "in depth and in detail," but it gave no indication how the participants reacted.

Al-Maliki on Wednesday was to show the draft to the National Security Council, a consultative body that includes himself, Talabani, the vice presidents, leaders of political blocs and the parliament speaker. If they agree, he will submit the draft to his Cabinet for their approval by two-thirds majority. The final step will be parliament's approval.

Followers of influential Shiite cleric Muqtada al-Sadr oppose any agreement that would keep U.S. soldiers in Iraq. And Shiite-dominated Iran, which wields considerable influence among some Shiite parties, also opposes the agreement.