Baghdad ? Secretary of State Condoleezza Rice brought Iraq’s leader a double-edged message Tuesday: praise for progress toward ending the nation’s sectarian rifts, but also a warning not to squander the momentum after many false starts on reconciliation.

The meeting with Prime Minister Nouri al-Maliki underscored Washington’s push for faster and bolder efforts to heal differences between the Shiite-led government and Iraq’s other main groups – Sunni Arabs who were sidelined by the fall of Saddam Hussein and Kurds enjoying an economic boom in their near-autonomous enclave.

The Iraqi parliament took an important step last week to open the way for low-ranking members of Saddam’s Baath party to reclaim government posts and pensions. Rice congratulated al-Maliki for the “quite remarkable” progress on national reconciliation.

But she pressed for more – telling al-Maliki not to lose a “golden opportunity” during President Bush’s final year in office to bring Sunni Arabs into a unity government, according to three Iraqi officials with knowledge of the talks.

The Iraqis spoke on condition of anonymity because they are not authorized to share the information with the media. Two attended meetings between Rice and Iraqi leaders. The third was briefed by a senior participant.

The officials said Rice further warned that the recent reduction of violence in Iraq could prove fleeting if the country’s main groups did not reach an enduring agreement on the future of the country.

The fragility of the security gains was highlighted shortly after Rice’s visit. At least five mortars landed in the U.S.-protected Green Zone, home to the U.S. Embassy and many Iraqi government offices. There were no immediate reports of casualties or serious damage.

Rice split off from Bush’s Mideast tour for Tuesday’s unannounced visit to Baghdad.