Iraq's power grid is on the brink of collapse because of insurgent sabotage, rising demand, fuel shortages and provinces that are unplugging local power stations from the national grid, officials said. Electricity Ministry spokesman Aziz al-Shimari said Saturday power generation nationally is only meeting half the demand, and there had been four nationwide blackouts over the past two days. The shortages across the country are the worst since the summer of 2003, shortly after the US-led invasion to topple Saddam Hussein, he said. Power supplies in Baghdad have been sporadic all summer and now are down to just a few hours a day, if that. The water supply in the capital has also been severely curtailed by power blackouts and cuts that have affected pumping and filtration stations. Karbala province south of Baghdad has been without power for three days, causing water mains to go dry in the provincial capital, the Shiite holy city of Karbala. "We no longer need television documentaries about the Stone Age. We are actually living in it. We are in constant danger because of the filthy water and rotten food we are having," said Hazim Obeid, who sells clothing at a stall in the Karbala market. Electricity shortages are a perennial problem in Iraq, even though it sits atop one of the world's largest crude oil reserves. The national power grid became decrepit under Saddam Hussein because his regime was under UN sanctions after the Gulf War and had trouble buying spare parts or equipment to upgrade the system. The power problems are only adding to the misery of Iraqis, already suffering from the effects of more than four years of war and sectarian violence. Outages make life almost unbearable in the summer months, when average daily temperatures reach between 110 (43.3 Celsius) and 120 degrees (48.8 Celsius). One of the biggest problems facing the national grid is the move by provinces to disconnect their power plants from the system, reducing the overall amount of electricity being generated for the entire country. Provinces say they have no choice because they are not getting as much electricity in return for what they produce, mainly because the capital requires so much power. "Many southern provinces such as Basra, Diwaniyah, Nassiriyah, Babil have disconnected their power plants from the national grid. Northern provinces, including Kurdistan, are doing the same," al-Shimari said. "We have absolutely no control over some areas in the south," he added. "The national grid will collapse if the provinces do not abide by rules regarding their share of electricity. Everybody will lose and there will be no electricity winner," al-Shimari said. He complained that the central government was unable to do anything about provincial power stations pulling out of the national system, or the fact some provinces were failing to take themselves off the supply grid once they had consumed their daily ration of electricity. Najaf provincial spokesman Ahmed Deibel confirmed to The Associated Press Sunday that the gas turbine generator there had been removed from the national grid. He said the plant produced 50 megawatts while the province needed at least 200 megawatts. "What we produce is not enough even for us. We disconnected it from the national grid three days ago because the people in Baghdad were getting too much, leaving little electricity for Najaf," he said. Compounding the problem, al-Shimari said there are 17 high-tension lines running into Baghdad but only two were operational. The rest had been sabotaged. "What makes Baghdad the worst place in the country is that most of the lines leading into the capital have been destroyed. That is compounded by the fact that Baghdad has limited generating capacity," al-Shimari said. "When we fix a line, the insurgents attack it the next day," he added. Fuel shortages are also a major problem. In Karbala, provincial spokesman Ghalib al-Daami said a 50-megawatt power station had been shut down because of a lack of fuel, causing the entire province to be without water and electricity for the past three days. He said sewage was seeping above ground in nearly half the provincial capital because pump trucks used to clean septic tanks have been unable to operate due to gasoline shortages. The sewage was causing a health threat to citizens and contaminating crops in the region. Many people who normally would rely on small home generators for electricity cannot afford to buy fuel. Gasoline prices have shot up to nearly $5 a gallon, Karbala residents say, a price that puts the fuel out of range for all but the wealthy. "We wait for the sunset to enjoy some coolness," said Qassim Hussein, a 31-year-old day laborer in Karbala. "The people are fed up. There is no water, no electricity, there is nothing, but death. I've even had more trouble with my wife these last three days. Everybody is on edge." Iraq has the world's third-largest proven oil reserves, behind Saudi Arabia and Iran. But oil production has been hampered by insurgent and saboteur attacks, ranging from bombing pipelines to siphoning off oil. The attacks have cost the country billions of dollars since the 2003 US invasion. Dilapidated infrastructure has also hindered refining, forcing Iraq to import large amounts of kerosene and other oil products. The electricity problems come as leaders are trying to deal with a political crisis that erupted when the country's largest bloc of Sunni political parties withdrew from the government. US President George W. Bush called Iraqi President Jalal Talabani and Vice President Adel Abdel-Mahdi to urge them to try to preserve political unity in the country, where the government of Prime Minister Nouri al-Maliki is under a stiff challenge from rival political forces and insurgents. Talabani, a Kurd, and Abdel-Mahdi, a Shiite, provided few details of the conversations in statements released by their offices. But both men have been involved in trying to solve the crisis. Elsewhere, the US military announced the death of a Marine during combat Thursday in Iraq's western Anbar province. The US military also issued a statement saying its forces killed four suspects and captured 33 others Saturday in raids in northern Iraq and along the Tigris River Valley. In northern Iraq, a prison riot was brought under control two days after it broke out when Iraqi guards prepared to move inmates into an isolation unit and US soldiers surrounded the facility. The riot at Badoosh prison outside Mosul, about 220 miles northwest of Baghdad, involved nearly 65 inmates. Iraqi guards killed one inmate who was trying to escape from the prison yard and wounded two others inside the prison, the US military said in a statement. The US military said American troops did not fire any rounds during the disturbance and no US or Iraqi troops were wounded.