US troops in Iraq say they have uncovered a bomb-making factory in the south of the capital, Baghdad.
Many Iraqis have also been killed in car bomb attacks
A large cache of weapons and cash was also found at the unidentified site, a US military statement said.
Bomb-making equipment, weapons and ammunition were found in raids at other locations - and 51 people have been taken in for questioning.
The discovery coincided with one of the worst days of violence since the new Iraqi government took power on Monday.
- At least five members of the Iraqi security forces were killed and several more wounded in an attack on a checkpoint in the town of Mahmudiya south of Baghdad. One report said they were guarding an oil pipeline
The Iraqi authorities confirm Ihsan Karim, in charge of the Iraqi investigation into the oil-for-food scandal, has died of wounds received when his car was blown up in Baghdad on Thursday
A US marine died of wounds received in an attack in al-Anbar province west of Baghdad on Friday.
A British soldier has been wounded in a roadside bomb attack in the southern city of Basra.
The Iraqi government is expected to announce new legislation to tackle the insurgency on Saturday.
Officials say the National Safety Law could allow the authorities to impose emergency laws in specific areas of the country for set periods of time.
Bombs 'being completed'
The US said the Baghdad raid uncovered vehicles loaded with explosives for use as car bombs.
"These discoveries deal a blow to anti-Iraqi forces," Lt Col James Hutton said in a statement.
"Soldiers from the 1st Battalion 8th Cavalry Regiment discovered four potential VBIED vehicles in various stages of completion and three safes containing more than 12m Iraqi dinars ($8,750) and various documents and ledgers," the US military said.
Also found during the raid were:
"Three individuals were taken in for questioning," the statement said.
- Five AK-47 rifles
- approximately 500 rounds of ammunition
- computer boards, wires
- a sight for a rocket-propelled grenade launcher.
On another raid, US soldiers found "partially assembled improvised explosive devices, rocket-propelled grenade launchers, eight RPG [rocket propelled grenade] rounds, approximately 50 pounds of C-4 explosives, TNT, five blasting caps, one detonator and other various munitions".
"The soldiers detained 30 individuals found at the site," the statement said.
Eighteen more people were detained in raids on eight other locations.
They are suspected of involvement in bomb attacks that have killed two soldiers in the area.
"The soldiers believe they have captured the financier, the explosive device manufacturer, the spotter, and the triggerman," the statement said.