The number of Iraqi civilian deaths last month fell by more than 50 percent, while 64 American forces died, the lowest monthly toll since July 2006, according to figures compiled by the U.S. military, the Iraqi government and The Associated Press.

The sharp decline in death tolls signaled a U.S. success, if only temporary, in bringing down violence in Baghdad and surrounding regions since Washington completed its infusion of 30,000 more troops on June 15.

The figures for Iraqi civilian deaths were dramatic, falling from 1,975 in August to 922 last month, a decline of 53.3 percent. The breakdown in September was 844 civilians and 78 police and Iraqi soldiers, according to Iraq's ministries of Health, Interior and Defense.

In August, AP figures showed 1,809 civilians and 155 police and Iraqi soldiers were killed in sectarian violence.

The civilian death toll has not been so low since June 2006, when 847 Iraqis died.

"There is no silver bullet or one thing that equates as a reason to the drop in Iraqi and Coalition casualties and deaths," said Col. Steven Boylan, spokesman for U.S. commander Gen. David Petraeus.

But he credited increased U.S. troop strength, saying that has allowed American forces to step up operations against Al Qaeda in Iraq.

Over the weekend, U.S. and Iraqi forces killed more than 60 insurgent and militia fighters in intense battles, with most of the casualties believed to have been al-Qaida fighters, officials said.

U.S. aircraft killed more than 20 Al Qaeda in Iraq fighters who opened fire on an American air patrol northwest of Baghdad, the U.S. command said Sunday.

The firefight between U.S. aircraft and the insurgent fighters occurred Saturday about 17 miles northwest of the capital, the military said.

The aircraft observed about 25 Al Qaeda insurgents carrying AK-47 assault rifles — one brandishing a rocket-propelled grenade — walking into a palm grove, the military said.

"Shortly after spotting the men, the aircraft were fired upon by the insurgent fighters," it said.

The military did not say what kind of aircraft were involved, but the fact that the fighters opened fire suggests they were low-flying Apache helicopters. The command said more than 20 of the group were killed and four vehicles were destroyed. No Iraqi civilians or U.S. soldiers were hurt.

Iraq's Defense Ministry said in an e-mail Sunday that Iraqi soldiers had killed 44 "terrorists" over the past 24 hours. The operations were centered in Salahuddin and Diyala provinces and around the city of Kirkuk, where the ministry said its soldiers had killed 40 and arrested eight. It said 52 fighters were arrested altogether.

The ministry did not further identify those killed, but use of the word "terrorists" normally indicates Al Qaeda.

In a separate operation, U.S. forces killed two insurgents and detained 21 others during weekend operations against Al Qaeda.

Intelligence led to a raid early Sunday that netted what the U.S. military called 15 rogue members of the Mahdi Army militia at an undisclosed Baghdad location.

The mainstream of the militia, the armed wing of anti-American cleric Muqtada al-Sadr's organization, has been ordered by the religious leader to stop attacks on U.S. and Iraqi forces.

But many one-time members of the group have split off and are acting independently of al-Sadr's control. Some have gone to Iran for training and are receiving weapons and financing from the Islamic regime in Tehran.

The U.S. Embassy, meanwhile, joined a broad swath of Iraqi politicians — both Shiite and Sunni — in criticizing a nonbinding U.S. Senate resolution seen here as a recipe for splitting the country along sectarian and ethnic lines.

The Senate resolution, adopted last week, proposed reshaping Iraq according to three sectarian or ethnic territories. It calls for a limited central government with the bulk of power going to the country's Shiite, Sunni or Kurdish regions, envisioning a power-sharing agreement similar to the one that ended the 1990s war in Bosnia. Sen. Joseph Biden, D-Del., was a prime sponsor.

In a highly unusual statement, the U.S. Embassy said resolution would seriously hamper Iraq's future stability.

"Our goal in Iraq remains the same: a united, democratic, federal Iraq that can govern, defend, and sustain itself," the unsigned statement said.

"Iraq's leaders must and will take the lead in determining how to achieve these national aspirations. ... attempts to partition or divide Iraq by intimidation, force or other means into three separate states would produce extraordinary suffering and bloodshed," it said.

The statement came just hours after representatives of Iraq's major political parties denounced the Senate proposal.

The Kurds in three northern Iraqi provinces are running a virtually independent country within Iraq while nominally maintaining relations with Baghdad. They support a formal division, but both Sunni and Shiite Muslims have denounced the proposal.

At a news conference earlier in the day, at least nine Iraqi political parties and party blocs — both Shiite and Sunni — said the Senate resolution would diminish Iraq's sovereignty and said they would try to pass a law to ban any division of the country.

"This proposal was based on the incorrect reading and unrealistic estimations of Iraq's past, present and future," according to a statement read at a news conference by Izzat al-Shahbandar, a representative of the secular Iraqi National List.

On Monday, the leader of the country's largest Sunni Arab political group, Adnan al-Dulaimi, joined his colleagues in denouncing the plan. Al-Dulaimi assured citizens his party "would fight for the sake of Iraq's unity."