The military buildup in Iraq is about to end.

But as the last of the five additional combat brigades now heads home, it leaves the country far safer than it was a year ago. Yet Iraq is still not ready to stand alone.

The departure of the 2nd Brigade, 3rd Infantry Division will lower U.S. troop levels there to roughly 142,000 U.S. personnel by mid-July ’ at least 7,000 more than before the buildup began early last year. But it also sets up pivotal questions about how many more can come home in this election year, and whether the decline in violence can be maintained by the fledgling Iraqi security forces.

Two reports released Monday laid out significant political, economic and security progress in Iraq. But both cautioned that the country remains unstable and volatile.

The quarterly Iraq progress report issued by the Pentagon warned that Iran and Syria continue to provide safe havens for terrorists, and allow them to travel across the borders into Iraq. It also repeated concerns that Iran’s Quds Force, an elite unit of its Revolutionary Guards, continues to supply both weapons and training for militants in Iraq.

On the domestic side, the report sounded a pessimistic tone, saying the government of Iraq still struggles to enact its budget and fund large projects to rebuild its infrastructure.

The government, it said, ’lacks the ability to execute programs on the scale required,’ and economic improvements remain ’fragile, reversible and uneven.’

Al-Qaida, meanwhile, has been hobbled by the military buildup and subsequent improvement of Iraqi forces, and its areas of operation have shrunk, the report said. It warned, however, that al-Qaida is regrouping along the upper Euphrates River in Anbar Province.

The report details the spike in attacks during March and April when Iraqi forces clashed with militias in Basra, triggering violence in Sadr City and a wave of bombings against coalition troops in the International Zone.

As a result, daily attacks in Baghdad shot up by 54 percent compared with the previous three months, and attacks in Basra were up by 6 percent over that same period. While violence has now dropped off again, the report said militant leaders appear to have fled to Iran and the Maysan Province, setting up possible clashes in the future.

A second report, issued by the congressional Government Accountability Office, pointed to a lack of progress by Iraqi forces since just 10 percent can operate on their own. And it said the government continues to fall behind in meeting the demands for services, such as electricity.

Other data in the reports included:

’ Northern Iraq continues to be a problem area, with roughly half of all security incidents occurring there.

’ Most provinces in other parts of the country averaged less than one attack per day.

’ Civilian deaths in May were 75 percent lower than last July.