The top U.S. general in Iraq said Wednesday that Iraqi forces should be able to take over security with little coalition support as early as next year, even as bloodshed around the country killed at least 66 people.

Violence has spiked in recent days, with more than 200 people dying since the beginning of the week in clashes, bombings or shootings.

Gen. George Casey nonetheless said Iraqi troops are on course to eventually take over from coalition forces.

"I don't have a date, but I can see over the next 12 to 18 months, the Iraqi security forces progressing to a point where they can take on the security responsibilities for the country, with very little coalition support," Casey said.

His comments do not necessarily mean the United States will be pulling troops from the country, but American officials have always maintained that building up the Iraqi security forces is vital to any U.S. exit strategy.

CountryWatch: Iraq

A roadside bomb killed 24 people in Baghdad's largest and oldest wholesale market district, Shurja, where vendors sell food, clothing and home products from warehouses, stalls and shops. At least 35 people were wounded.

Earlier, an explosives-rigged bicycle blew up near an army recruiting center in Hillah, a city about 60 miles south of Baghdad, killing at least 12 people. A man posing as an army applicant planted the bomb-laden bicycle outside the recruiting center as volunteers gathered outside.

Hillah was the site of one of the worst bomb attacks in Iraq, when a suicide car bomber killed 125 national guard and police recruits in Feb. 2005.

Insurgents often target Iraqi army and police volunteers, as a way to discourage people from joining the security services.

The U.S. command reported that a Marine from the 1st Brigade of the 1st Armored Division was killed in action Tuesday in Anbar province.

And a family of five was wiped out in Buhriz, 35 miles north of Baghdad, when a roadside bomb struck their car.

Elsewhere in Iraq, the Diwaniyah health directorate reported that 40 people were still missing after an explosion Tuesday at an oil pipeline near the city, 50 miles south of the capital.

At least 36 people were killed and 45 injured in the explosion, the Interior Ministry said.

The city's health directorate said Wednesday that 40 people still missing could not be confirmed dead because their bodies had not been found.

The reason for Tuesday's explosion was not clear, but police Lt. Raid Jabir said several people had been siphoning fuel from the pipeline when the blast occurred.

The violence this week has included some of the fiercest fighting in months between the Iraqi army in Diwaniyah and Shiite militiamen loyal to radical cleric Muqtada al-Sadr.

The fighting Monday was significant because it pitted mostly Shiite Iraqi soldiers against the militia of one of the country's most prominent Shiite leaders.

It also illustrated the complexity of the security crisis in Iraq — with Sunni insurgents fighting U.S. troops in the west, Sunnis and Shiites killing one another in Baghdad and now Shiites battling Shiites in the south.

During a meeting with the governor of Diwaniyah two days ago in Najaf, al-Sadr deplored the violence, which he described as "individual acts," a spokesman said.

Sheik Mohamed Jamil, a spokesman for al-Sadr office in Najaf, told The Associated Press that the clashes "happened without instructions from the al-Sadr office in the city."

Al-Sadr led two uprisings against U.S. forces in 2004 but has since emerged as a major political figure.

The latest violence occurred despite U.S. and Iraqi officials' claims that a major security crackdown launched in Baghdad on Aug. 7.has lowered Sunni-Shiite killings there, which had risen in June and July.

On Monday, U.S. military spokesman Maj. Gen. William B. Caldwell said the murder rate in Baghdad had fallen by 46 percent from July to August and "we are actually seeing progress out there."

That figure could not be independently confirmed. An employee of the main Baghdad city morgue, Muyaid Matrood, said that as of Monday, his office had received 337 bodies of people who had died violently this month, excluding bombing victims. No we do not do we have any comparable number from other months?

Similar operations have curbed violence for limited periods of time in the past, only to have killings flare again once American forces left.

In other violence, according to police:

— A suicide bomber blew himself up inside a minibus in northwestern Kirkuk, killing three people and wounding 11 others in the predominantly Christian neighborhood of Arafa.

— A police patrol was hit by a roadside bomb overnight in the town of Balad Ruz, 20 miles north of Baqouba, leaving five policemen dead and one wounded.

— A mortar round fell near the home of an Iraqi army officer in a district of Baqouba, killing him.

— A roadside bomb targeting a police patrol in Muqdadiyah, 30 miles northeast of Baqouba, killed three civilians and wounded 10, including three policemen.

— Justice Ministry official Nadiya Mohammed Hassan was shot and killed along with her bodyguard and driver.

— Three carpet merchants were killed while being driven in a taxi, police said.

— In downtown Baghdad, three police officers were killed and 14 people were wounded when twin bombs struck a police patrol.

— An Iraqi army major was killed in Kut, 100 miles southeast of Baghdad, by a roadside bomb.

— Five bullet-riddled bodies turned up in Suwayrah, 25 miles south of Baghdad.

— A civilian driving in his car in northern Mosul was shot and killed, apparently after U.S. troops opened fire when the man's vehicle came too close to them.

— A 4-year-old girl was killed and her mother was wounded after Interior Ministry commandos fired on their car in Samarra, 60 miles north of Baghdad.

— A police captain was killed by a roadside bomb on a road leading from southern Basra to the Iranian border.