A car bomb exploded Thursday in Baghdad's biggest Shiite district, killing seven people and injuring 15, officials said.

Iraq's prime minister insisted that Iraqi forces were ready to take over security duties in most provinces despite rising violence.

US officials confirmed that the number of roadside bombs directed against US and Iraqi forces increased sharply last month, dramatizing the threat posed by the Sunni-led insurgency despite attention directed to sectarian violence in the capital.

The parked car exploded a little after noon near a market in Sadr City, inflicting the casualties and damaging many shops, said police Lt. Adil Salih.

The Iraqi army general command said in a statement that seven people were killed and 15 injured.

Residents said the number of casualties was relatively low because most people had finished their shopping early to escape the 120 degree heat that was forecast for Baghdad on Thursday.

Sadr City, a predominantly Shiite neighborhood, is one of the most tightly secured areas in Baghdad, patrolled by police as well as members of the Mahdi Army militia of the anti-US cleric Muqtada al-Sadr.

The security is to prevent attacks by Sunni insurgents, but the latest attack demonstrates the difficulties of controlling the seething sectarian violence, which has risen steadily since the Feb. 22 explosion at a Shiite shrine in Samarra. The bombing triggered a wave of reprisal killings and has raised fears of an all-out civil war.

The sectarian violence has diverted attention from the threat posed by Sunni Arab insurgents. But recent figures suggest that the insurgency is gaining strength despite setbacks, including the June 7 death of al-Qaida in Iraq leader Abu Musab al-Zarqawi, killed in an airstrike northeast of Baghdad.

US officials said that, in July, a total of 2,625 bombs exploded or were discovered before they could detonate. That was up sharply from the 1,454 bombs that went off or were discovered in January.

Of the bombs discovered in July, 1,666 of them exploded and the rest were detected. About 70 percent of them were directed at US-led forces. Twenty percent were directed at Iraqi security forces and 10 percent against civilians, the officials said.

They spoke on condition of anonymity because they were not authorized to release the figures.

Still, Prime Minister Nouri al-Maliki said government forces were ready to take over the country's security in most areas, a statement from his office said.

It quoted al-Maliki as telling the visiting Slovak prime minister, Robert Fico, that: "Iraqi forces are capable of taking over the security in most of the Iraqi provinces and will be able to fill the vacuum if the multinational forces withdraw." It did not elaborate.

Fico, who arrived Thursday on a 24-hour visit, had said last month that he plans to bring back the country's 104 soldiers, but gave no timetable. They are deployed in the southern Qadisiyah province, and are expected to hand over their duties to Iraqi forces, al-Maliki said.

Deputy Health Minister Adel Muhsin said Wednesday that about 3,500 Iraqis died in July in sectarian or political violence nationwide, the highest monthly death toll for civilians since the war started in March 2003.

Last week, the ministry said about 1,500 violent deaths were reported in the Baghdad area alone in July. US commanders are rushing nearly 12,000 US and Iraqi troops to the capital to try to end the carnage.

Also Thursday, Iraqi army soldiers raided two villages west of Kirkuk, 180 miles north of Baghdad, and arrested 50 suspected insurgents, said police Col. Khalil al-Zawbaie. He said 45 different weapons, a large quantity of explosives, and instructions for making and planting bombs were seized.

(Chinadaily.com via agencies August 18, 2006)