Snipers, cluster bombs and intense shelling are spreading panic in Misrata, an AFP reporter said on Monday, as a doctor reported 1,000 people killed in six weeks of fighting in the besieged city.
With fears growing that refugees will attempt a chaotic mass escape by sea from the city of 400,000, UN chief Ban Ki-moon called for a ceasefire and a political solution to the two-month-old conflict in Libya.
The International Organisation for Migration warned that the vast numbers wanting to flee Misrata, about 215 kilometres (130 miles) east of Tripoli, was threatening to overwhelm an international sea rescue operation.
The IOM said nearly 1,000 stranded people had been taken out on Monday, but that thousands more were awaiting rescue in increasingly perilous circumstances.
Hussein al-Fortia, a school headmaster-turned-rebel, said fighting had been "awful" over the past weeks, with forces loyal to Libyan leader Moamer Kadhafi attacking from three sides and firing rockets from kilometres (miles) away.
He did not know how many insurgent fighters there are. "Maybe there are 3,000, maybe 5,000 -- no one knows because we are not fighters."