No sign of Nato

The military difficulties were underlined when further details emerged of the death of British photographer Tim Hetherington, who was killed on Wednesday in a mortar attack along with a colleague, Chris Hondras. An Oscar-nominated filmmaker, Hetherington, 41, wrote in his last Twitter post on Tuesday: "In besieged Libyan city of Misrata. Indiscriminate shelling by Gaddafi forces. No sign of Nato." guardian

Drones can be used

Earlier this week Nato's commander, Lt Gen Charles Bouchard, described the situation within Misrata as being akin to "a knife fight in a phone booth". He said Gaddafi forces were hiding on the rooftops of mosques, hospitals and schools, and that they were shielding themselves behind women and children. guardian

Tim Hetherington and Chris Hondros killed

Two leading photojournalists have been killed covering escalating violence in Misrata, and two other western photographers working with them were injured.

Oscar-nominated British documentary-maker Tim Hetherington, 40, co-creator of the Sundance-winning documentary Restrepo, was killed covering fighting between Muammar Gaddafi's forces and the opposition.

Chris Hondros, 41, a US Pulitzer finalist who works for Getty Images, was also killed. His work has appeared in magazines and newspapers around the world. His awards include World Press Photo honours and the Robert Capa gold medal, one of the highest prizes in war photography. guardian