Nigerian President Olusegun Obasanjo has said he is "shocked and saddened" by the vandalisation of an oil pipeline that led to at least 260 deaths.
The intense heat hampered recovery efforts
Hundreds of people in a Lagos suburb were scooping fuel from a pipeline punctured by thieves when it exploded.
It took the emergency services hours to extinguish the flames and many of the bodies were burnt beyond recognition.
Some 2,000 people have died in similar incidents in recent years in Nigeria, which suffers frequent fuel shortages.
President Obasanjo blamed the tragedy on vandals damaging the pipeline and said he was sad that such vandalism continued despite his warnings that it was "not only illegal but a dangerous pursuit".
NIGERIA PIPELINE DISASTERS
May 2006: At least 150 killed in Lagos
Dec 2004: At least 20 killed in Lagos
Sept 2004: At least 60 killed in Lagos
June 2003: At least 105 killed in Abia State
Jul 2000: At least 300 killed in Warri
Mar 2000: At least 50 killed in Abia State
Oct 1998: At least 1,000 killed in Jesse
Adding his voice to the condolences, United Nations Secretary General Kofi Annan said the UN was ready to provide immediate assistance. and also to help assess gaps in disaster response.
Mr Annan also called for " a review of the country's fuel supply management, as well as a thorough regional review of risks that could lead to other environmental or technological disasters in West Africa."
Despite being Africa's largest oil producer, Nigerians often suffer fuel shortages because of corruption, poor management and infrastructure problems.
It appears that thieves broke into a pipeline passing through the Abule Egba area of Lagos early on Tuesday to siphon off large amounts of fuel.
Some time later, hundreds of local people had arrived on the site carrying jerry cans and plastic buckets when a vast explosion shook the neighbourhood.
The Nigerian Red Cross (NRC) says at least 260 people were killed and dozens were injured.
Some of those injured in the blast are believed to have gone into hiding to avoid arrest. Others may not have gone to hospital because they lack money to pay for treatment.
Lagos journalist Adeyinka Adewunmi witnessed the aftermath of the explosion.
"The pipelines are in a popular neighbourhood, very close to the express road, which I normally use for my journey to work," he told the BBC News website.
"I could see fire, state ambulances, ambulances of the Red Cross, firefighters, government officials. There were scores of dead bodies on the ground and injured people being carried into ambulances.
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