The statement, issued in the names of Iraqi Prime Minister Nuri al-Maliki and US Ambassador Zalmay Khalilzad, said such a calendar of measures would be based on goals developed by Iraq's own government with US support.
"The Iraqi government has made clear the issues that must be resolved with timelines for them to take positive steps forward on behalf of the Iraqi people," said the statement, issued in English by the US embassy.
"The United States fully supports their goals and will help make them a success," it added.
On Tuesday, Khalilzad announced that Iraq had agreed to meet certain "benchmarks" to disarm illegal militias and put in place political and economic reforms designed to placate the country's warring parties.
This angered Maliki, who on Wednesday gave a press conference of his own to declare: "Everyone knows that this government is a government of the popular will and no one may set a timetable for it."
Maliki's anger laid bare the tension in the working relationship between the governments at a delicate time for US President George W. Bush as he defends his strategy for victory in Iraq to an increasingly sceptical electorate.
Bush has been under pressure in Washington to force Maliki to speed up his programme of national reconciliation and move aggressively to disarm the sectarian militias behind much of the violence.
American officials have been at pains to insist publicly that the prime minister has their full support, while privately worrying that he lacks the political will to pull Iraq back from the brink of civil war.
Maliki has countered in a series of interviews by blaming the US for the disarray in the Iraqi security forces they are trying to build to replace the 142,000 US soldiers still fighting in the country.
"The government of Iraq is committed to a good and strong relationship with the US Government to work together toward a democratic, stable Iraq," the joint statement said.
The leaders vowed "to confront the terrorist challenges in light of the strategic alliance between the two countries."
Iraq is in the grip of a vicious sectarian conflict which claims more than 100 Iraqi lives per day and has undermined attempts to defeat a rebellion against the US-backed government and revive the shattered economy.
The plan outlined by the two governments over recent weeks has been for Maliki to oversee a joint political and military strategy to confront armed groups and co-opt their political backers into a peace process.
There will be changes to how Iraq's oil revenues are shared, a review of the constitution to secure minority rights, and the committee set up to purge members of the pre-invasion ruling elite from government will be reformed.
Both the US and Iraqi governments appear to agree on the broad outlines of the plan -- and Bush this week endorsed Maliki as "the right man for the job" -- but differences in emphasis have led to tension.
In particular, some US commanders have been pushing the prime minister to take a tougher stance on the powerful Shiite militias linked to parties in his coalition, which now fight almost daily gunbattles with security forces.
Maliki has instead pushed to resolve the crisis through dialogue.

Copyright AFP (Agence France-Presse), 2006