Misrata, Libya (CNN) -- Heavy fighting that began at dawn and continued past midnight Friday left at least 31 people dead Saturday in the western Libyan city of Misrata, where rebel forces thwarted efforts by government forces to enter from the west and south. By the end of Friday, more than 160 others had been wounded, said medical sources at the city's Hekmah Hospital. Friday's casualties were the heaviest in a month, Dr. Khaled Abu Falgha said. Medics chanted, "The martyrs are beloved to God" every time a patient died, he said. The rebels said Gadhafi's forces also shelled nearby Zlitan, as well as rebel positions in Dafniya. Tanks were rolling in and witnesses on the frontline said pro-Gadhafi forces were firing rockets and missiles.
@highlight
At a field hospital, doctors didn't take the time to count the dozens of wounded
@highlight
Letter purportedly from Gadhafi appeals to "the great Democracy" for assistance
@highlight
Sen. Levin "satisfied that Gadhafi's military has been severely degraded"
@highlight
Sen. Sessions "not sure we are acting with decisive abilities"
"Let's stop the destruction and begin the negotiations to find a peaceful solution for @placeholder," it says.