Moammar Gadhafi's forces rocketed the main fuel depot in Misrata on Saturday, intensifying a two-month siege on the rebel-held city that has claimed many civilian lives and prompted warnings of a humanitarian crisis.
Government forces sent Grad rockets slamming into the depot, which contains vital stores of fuel for cars, trucks, ships and generators powering hospitals and other key sites in a city left darkened by electricity cuts, residents said.
Fuel tanks were engulfed in flames hours after the early morning attack, as firefighters battled the blazes. No one was injured, a doctor said.
The attack raised fears of shortages, though some of the fuel had already been moved to other sites in anticipation of such a strike.
"After a few days, we may have a big crisis," said Misrata resident Mohammed Abdullah, speaking by Skype since regular phone lines have been cut. "He wants to bring Misrata's people to their knees, and make them surrender. Surrendering is impossible."
Misrata — the rebels' only stronghold in western Libya — has experienced some of the heaviest fighting of the conflict. Most of the rebel forces are based in the east, using the city of Benghazi as their headquarters.
A rebel spokesman in Benghazi, Abdel-Hafidh Ghoga, confirmed reports by Misrata residents that a white helicopter "disguised with Red Cross insignia" by Gadhafi's forces was seen dropping anti-ship mines into the port.
Ghoga also said that Italy has agreed to sell arms to the rebels, although the Italian Foreign Ministry denied the claim.
The rebels have been pleading for heavy arms for weeks, and Ghoga said weaponry from Italy was expected soon, although he gave no precise date.
"When we get the arms we will finish the job," he said.
At Misrata's hospital, a doctor said the latest bombing could cause a severe shortage of fuel for generators. He spoke on condition of anonymity for security reasons.
Amnesty International says Gadhafi's forces may have committed war crimes in Misrata and have used weapons designed for the battlefield and not for residential areas, resulting in civilian casualties and "creating a situation of terror."
The humanitarian situation is rapidly deteriorating because of regime attempts to tighten its siege and block access by sea, Amnesty says.
Libyan troops besieging the city of 300,000 by land recently stepped up shelling of Misrata's port to close the city's last lifeline. Hundreds of people have been killed in Misrata since February, medics say.
Amnesty said the attempted blockade of the port has made it even more difficult to bring in supplies. There is no electricity or running water in large parts of the city, and food supplies are dwindling, it said.
About a week ago NATO warships intercepted several boats laying anti-shipping mines outside Misrata's harbor. More recently, residents said mines were dropped from helicopters with Red Cross insignia.
The government has not acknowledged the mine-laying but says it is trying to prevent weapons shipments from reaching the rebels by sea.
Government officials deny wrongdoing by Libyan troops, including shelling of civilian areas. Libya's deputy foreign minister, Khaled Kaim, said Thursday that the military has decided to block ships from reaching Misrata, but would not discuss the tactics by regime loyalists.
The government said aid ships would be allowed to pass the blockade if they coordinate with the regime.
El Deeb reported from Cairo.