In lightning visits to training bases around the country, Rumsfeld told US troops they could "go home with honor" once Iraqi forces were able to defeat insurgents.

The latest insurgent attack underlined how vulnerable those forces still are.

In Balad Ruz, some 65 km northeast of the capital, Iraqi forces were lured into a death trap when they received a tip that a car bomb attack was being planned against the local Imam Hussein mosque.

"Security was deployed around the mosque to search for the car but, when they found it, another one went off," said officer Maher Salah.

Nine civilians and three policemen were killed, he said, adding that another body had not been identified and 23 more people were wounded.

There was no immediate claim of responsibility, but a similar attack against a Shia mosque in Baghdad three weeks ago was claimed by the network of al-Qaeda's frontman in Iraq, Abu Musab al-Zarqawi.

The deadly trap was sprung as the dust still settled in the lawless town of Salman Pak, some 33km southeast of the capital, following a spectacular attack Thursday by hordes of gunmen against police forces.

A fierce battle, which lasted several hours and saw US gunships come into action, left 10 policemen and 20 insurgents dead, another 75 policemen wounded and some 45 police cars destroyed.

"When we arrived, the shops were shut and the empty streets lined with photos of Saddam Hussein and calls for jihad (holy war)," said one survivor from his hospital bed. "Then armed men attacked us from everywhere. We tried to withdraw, but each street we took turned out to be a new trap."

In further violence, at least 11 people were killed at a bakery in the capital while another 12 Iraqis, mostly security forces, died in attacks elsewhere.

The latest unrest provided a bloody backdrop to the visit to Iraq by Rumsfeld, who flew from France to assess the impact of the January 30 elections and the readiness of Iraqi forces who will eventually take over from US troops.

The highest-ranking US official to visit Iraq since the landmark polls, he made his first stop in the strife-torn northern city of Mosul, the site of a bloody attack on a US base in December that killed 22 people.

He told several hundred soldiers, including some Iraqis, gathered at Mosul's airport that it would "take some time" to train security forces but the Iraqis must prepare themselves.

"Because it is the Iraqis who are going to have to, over time, defeat the insurgents. It is their country. It is their responsibility.

"Once they have confidence and capacity and capability, our forces, coalition forces, will be able to go home. And go home with the honour you will have earned," he said.

Rumsfeld expressed hope that an improving security situation will eventually allow a reduction in US forces but would give no timeline.

"I sense that the coalition effort is well organized, focused and that the professionalism of these units is advancing," he said.

Meanwhile, a recount of some 300 ballot boxes from the January 30 elections that had delayed the announcement of final results was still underway, electoral commission member Farid Ayar said.