By Hamid Ould Ahmed
ALGIERS (Reuters) - Forces loyal to Libyan leader Muammar Gaddafi killed 18 civilians in the city of Misrata on Tuesday and government troops are still firing tank shells and fighting skirmishes with rebels, a rebel spokesman said.
But a blockade of Misrata's Mediterranean port by pro-Gaddafi forces has now ended, allowing two ships to deliver humanitarian aid and evacuate people wounded in the fighting, the spokesman told Reuters by telephone.
Misrata, Libya's third-largest city, is the only big rebel stronghold left in the west of the country. Residents say it has been under siege for weeks by pro-Gaddafi forces and that dozens of people have been killed.
"Yesterday was a difficult day. Eighteen civilians were killed," said the spokesman, called Mohammed. Rebels had previously said nine civilians had been killed in fighting on Tuesday.
"There are skirmishes today. Tanks bombard the city every now and then," said Mohammed. "Snipers are still positioned in Tripoli Street (in the center of Misrata)."
But he said the main body of the pro-Gaddafi forces had not been able to enter the city center. "They are encircling it," said Mohammed.
Reports from Misrata, which is 200 km (130 miles) east of Tripoli, could not be verified independently because Libyan officials have prevented journalists from reporting freely from the city.
The rebel spokesman said that shortages of food and medical supplies had been eased after aid ships docked at the port, which, residents said, had until this week been blockaded by the pro-Gaddafi navy and coastguard vessels.
The U.S. Navy's Sixth Fleet said on Tuesday it had attacked three Libyan ships near Misrata to stop them firing at merchant ships at the port.
"The port is totally open now. It is ready to receive any aid," said the rebel spokesman.
"One ship from Tunisia and another from Malta came in yesterday with food. The Tunisian ship took about 100 wounded people for treatment."
John Drake, senior risk consultant with UK based security firm AKE, citing sources in Misrata, said vessels can call at the port there but it is hazardous because of the fighting going on in the city.
"An aid vessel arrived at the harbour at around 1200 local time today with medical provisions on board," he said.
"The main violence is located in the town, whereas the harbour is a little to the east, although it was subjected to artillery fire a few days ago."
(Additional reporting by Jonathan Saul in London; Writing by Christian Lowe; Editing by Giles Elgood)