Baghdad, Iraq ? Thunderous car bombs shattered a crowded marketplace Monday in the heart of Baghdad, triggering secondary explosions, engulfing an eight-story building in flames and killing at least 78 people in the latest in a series of similar attacks aimed at the country’s Shiite majority.

The blasts in three parked cars obliterated shops and stalls and left bodies scattered among mannequins and other debris in pools of blood. Dense smoke blackened the area and rose hundreds of feet from the market district on the east bank of the Tigris River. Small fires, fueled by clothing and other goods, burned for hours in the rubble-strewn street as firefighters battled blazes in two buildings.

“Where is the government? Where is the security plan?” survivors screamed. “We have had enough. We have lost our money and goods and our source of living.”

The attack appeared timed to coincide with the first anniversary – on the Muslim lunar calendar – of the bombing of a Shiite shrine in the town of Samarra north of Baghdad, an al-Qaida provocation that unleashed the torrent of sectarian bloodletting that has gripped the capital for months.

Monday’s bombings wrecked the Shorja market, Baghdad’s oldest, a day after joint U.S. and Iraqi forces temporarily sealed an adjacent neighborhood. The operation was part of the latest Baghdad security push to which President Bush has committed an additional 21,500 American troops. The U.S. military would not say if it had increased security patrols against potential violence on the Samarra anniversary.

Nationwide, 139 people were killed or found dead in violence Monday, according to police reports. About 30 minutes before the attack on the market, a suicide bomber detonated an explosives vest in a crowd near a popular falafel restaurant in the nearby Bab al-Sharqi area. Nine people were killed and 19 wounded.

A 15-minute period of commemoration in the capital marking the February 2006 attack on the al-Askariya shrine had just ended when the attack on the market took place.

The sound of two of the blasts was caught on tape as Prime Minister Nouri al-Maliki was delivering a speech live on television from the Cabinet building in the heavily fortified Green Zone at the end of the commemoration.

The Shiite prime minister didn’t flinch – though his bodyguards did – as he called for unity and said he was optimistic about the U.S.-Iraqi security sweep that officials said will gain momentum this week.

“We have great faith in our security services, army and police who have proved that they are a real protective force for this country, and we have faith that Iraqis have realized that there will be no future for this country unless terrorism is curbed,” he said.

Iraqis grieve amid the rubble after a double car bomb attack in Baghdad, Iraq. A series of explosions tore through two downtown markets Monday, killing at least 78 people and wounding 160 in the latest act of carnage to strike the commercial center of the capital.

Brig. Abdul-Karim Khalaf, the Interior Ministry spokesman, told Iraqiya state television that three suspects were arrested – an Iraqi and two foreigners – in the attack on the marketplace.

The car bombs exploded within seconds of each other. One of the cars was parked near the entrance to a parking garage under one of the two targeted buildings, about 200 yards apart.

Ambulances and pickup trucks rushed many of the 166 wounded to nearby al-Kindi Hospital in the largely Shiite neighborhood, which has been hit by a series of deadly bombings this year.

Sahib Abbas, 50, who owns a menswear shop in one of the targeted buildings, watched the recovery efforts in a daze and barefoot, his face covered with soot. “Hundreds of thousands of dollars were lost in this bombing,” he said.

Many shopkeepers were caught in the second blast as they ran into the street to see what had happened after the first bombing.

“I cannot go back to my shop now,” Abbas said. “Who is going to compensate us for our losses? All the money we gathered all our lives is gone in a moment. I cannot talk any more. The source of my children’s living is lost.”