BENGHAZI, Libya (Reuters) - A chartered ship evacuated nearly 1,000 foreign workers and wounded Libyans from Misrata on Monday as government artillery bombarded the besieged city that has come to symbolize the struggle against Muammar Gaddafi's rule.
"We wanted to be able to take more people out but it was not possible," said Jeremy Haslam, who led the International Organization for Migration (IOM) rescue mission.
"Although the exchange of fire subsided while we were boarding ... we had a very limited time to get the migrants and Libyans on board the ship and then leave."
A rebel spokesman said bombardments pounded Misrata for a fifth day on Monday after shelling killed 17 people and wounded about 100, mostly civilians, on Sunday.
Libya's third-largest city, Misrata is the rebels' main stronghold in the west and has been under siege by pro-Gaddafi forces for the past seven weeks. Evacuees say conditions there are becoming increasingly desperate and hundreds of civilians are believed to have been killed.
"The Gaddafi forces are shelling Misrata now. They are firing rockets and artillery rounds on the eastern side -- the Nakl el Theqeel (road) and the residential areas around it," Abdubasset Abu Mzeireq said on Monday morning.
The Ionian Spirit steamed out of Misrata carrying 971 people, most of them weak and dehydrated migrants mainly from Ghana, the Philippines and Ukraine, heading for the rebel stronghold of Benghazi in eastern Libya.
It was second vessel chartered by the IOM, which took out nearly 1,200 migrants from Misrata last Friday.
Among the rescued group were 100 Libyans, including a child shot in the face, the IOM said in a statement.
"We have a very, very small window to get everyone out. We do not have the luxury of having days, but hours," said IOM Middle East representative, Pasquale Lupoli.
"Every hour counts and the migrants still in Misrata cannot survive much longer like this."
Pro-Gaddafi forces have also kept up an offensive on the rebels' eastern frontline outpost of Ajdabiyah, which rebels want to use as a staging post to retake the oil port of Brega, 50 miles to the west.
One witness said he saw around a dozen rockets land near the western entrance to Ajdabiyah on Sunday and many fighters fled as explosions boomed across the town.
Sunday marked a month since the U.N. Security Council passed a resolution authorizing force to protect civilians in Libya, leading to an international air campaign.
But despite NATO air strikes against Gaddafi's armor, rebels have been unable to hold gains in weeks of back-and-forth fighting over the coastal towns in eastern Libya.
With NATO troops bogged down in Afghanistan, Western countries have ruled out sending ground troops, a position reinforced by the British prime minister on Sunday.
"What we've said is there is no question of invasion or an occupation -- this is not about Britain putting boots on the ground," David Cameron told Sky News in an interview.
Scores of volunteer fighters and civilian cars carrying men, women and children on Sunday streamed east from Ajdabiyah up the coast road toward Benghazi, where the popular revolt against Gaddafi's 41-year rule began in earnest on February 17.
The United States, France and Britain said last week they would not stop bombing Gaddafi's forces until he left power, although when or if that would happen was unclear.