A day after U.S. Defense Secretary Robert Gates stated in Baghdad that the goal of a stable and democratic Iraq was within reach, General David Petraeus said Thursday that "nobody in uniform is doing victory dances in the end zone."

Petraeus told reporters traveling with Gates: "We work hard to build up on the progress made … But we have to be careful not to feel too successful."

After arriving in Iraq unannounced on Wednesday, Gates declared that violence in the country had dropped to the lowest levels since the bombing of a Shiite shrine in Samarra two years ago unleashed a bloody spate of Shiite-Sunni strife.

But Petraeus' assessment seemed to be based more on realities on the ground, taking into consideration the anti-U.S. insurgency and fluctuating al-Qaida operations in the country torn by war since the U.S.-led invasion in March 2003.

"Certain days we certainly feel very good, but there are still attacks. We have seen continued improvements … but there is hard work still to be done and issues to be addressed," the general said.

His remarks came exactly one year after a U.S. bipartisan Iraq Study Group concluded that U.S. President George W. Bush's war strategy in Iraq had failed and described the situation in Iraq as "grave and deteriorating."

Bush responded to the report by declaring a 30,000 U.S. "troop surge" to Iraq, led by Petraeus who brought them into the country. The top U.S. commander had previously said the surge had produced benefit to the country, but in September announced to Congress a possible U.S. troop reduction.

U.S. troop casualties in November dropped to 35, the lowest monthly rate since last May. At least 3,886 American troops have been killed since March 2003 and tens of thousands of Iraqis have died since.

Petraeus Thursday cited the rise of Iraqi security personnel, the rejection of al-Qaida by Sunni Arabs, a six-month ceasefire by anti-U.S. Shiite cleric Moqtada Sadr, and increased support from neighboring countries as reasons for the decline in violence.

He added the troops were pursuing al-Qaida fighters as they were increasingly being chased out by Sunni tribes that turned against the group in the past year.

Other U.S. military officials reportedly claimed Thursday that al-Qaida elements have been heading to northern Iraq, including the provinces of Nineveh, Kirkuk, and Salaheddin, after they lost ground in Baghdad and predominantly Sunni areas where violence has declined.

Gates' first stop Wednesday was in Mosul, in the north, in which he was briefed by ground commanders on activities in and around Nineveh. He said Mosul was witnessing increased militant activities, indicating the migration of al-Qaida fighters northward.

Meanwhile, U.S. authorities in Iraq have been careful not to show much satisfaction toward what could be an Iranian reduction of aid to anti-U.S. insurgents, although "we have seen a reduction of signature attacks [explosively formed penetrators]," according to Petraeus.

U.S. forces have accused the Iranians of supplying Iraqi insurgents with armor-piercing bombs, but military officials more recently said that discoveries of arms and ammunition caches indicate that Iran had "reduced shipments of rockets and EFPs to Iraqi insurgents." And Gates said in September that Tehran had assured Baghdad of helping to stop the flow of these bombs, although Iran has consistently denied assisting insurgents.

"We are all in a wait-and-see mode," Petraeus said Thursday, adding that "we are hopeful Iran will take up this promise to stop."

Last month, the U.S. forces in Iraq released nine of 20 Iranians they arrested over the past two years on suspicion of supplying arms and training militias targeting American troops that Washington said caused the death of 200 soldiers.

The move paved the way for arranging a third round of talks between the United States and Iranian ambassadors in Baghdad, expected to be held this month, to discuss Iraqi security, which Tehran insists can only be restored with a U.S. withdrawal.

The two sides held two sets of talks in May and July, and another was held on an expert level in August. But neither side reported any progress on how to cooperate on restoring security to the war-ravaged country.

The two countries, the major adversary power brokers in Iraq, have not had diplomatic ties since the 1979 Islamic revolution in Iran.

This week's assessment by the U.S. intelligence community that Iran had halted its nuclear weapons program, which sharply contrasted with the Bush administration's claims of its atomic capabilities, could play a positive factor in their negotiations over Iraq.