At least 29 people were killed when a blast ripped through scavengers siphoning petrol from pools around a breach in a disused pipeline in central Iraq last night, health officials said.
Dozens more were missing and may have been killed.
A Reuters reporter at the rural site near Diwaniya, 180 km (110 miles) south of Baghdad, saw 15 charred and mutilated bodies, including that of a boy. The explosion wounded 26 people, who were taken to area hospitals with severe burns.
"Some of the wounded have burns in 75 per cent of their bodies," Hamid Jaafi, a health official in Diwaniya told Reuters, adding the death toll is expected to climb.
He said relatives had reported between 30 and 40 people missing after the explosion, pushing the possible death toll to about 70, although that could not be confirmed.
Witnesses said the blast, which is under investigation, occurred at 6pm, while a group of people were scooping fuel from two large pools.
Despite having the world's third largest proven reserves of oil, Iraq is gripped by a fuel crisis blamed on sabotage attacks, ageing infrastructure and rampart corruption.
Fuel prices have soared as the Iraqi government phases out subsidies under an International Monetary Fund deal.
Prime Minister Nuri al-Maliki said the government was working to ease the crisis, a source of anger for Iraqis. Smuggling and a black market for petrol products are thriving.
"I bless the enormous efforts that (the Oil Ministry) has made in overcoming the fuel crisis that citizens are facing lately," he told reporters at the Oil Ministry in Baghdad. The government wants to liberalise import rules on fuel products.