* Rebels say pro-Gaddafi forces firing mortars on houses
* Residents, seeking safety, flee districts under attack
* Rebels voice anger at NATO for not doing more
By Hamid Ould Ahmed and Mariam Karouny
ALGIERS/BEIRUT, April 7 (Reuters) - People in the Libyan city of Misrata are crammed five families to a house in the few safe districts to try to escape mortars raining down from government forces, a rebel spokesman said on Thursday.
Troops loyal to Libyan leader Muammar Gaddafi have mounted mortars on the rooftops of buildings, allowing them to extend their range into almost every part of the city, said the rebels.
Misrata is the only big rebel stronghold left in the west of Libya, but weeks of artillery attacks and sniper fire have shrunk the parts of the city controlled by the rebels — despite airstrikes by NATO warplanes aimed at protecting civilians.
“It does not seem there is a safe place in Misrata any more,” the spokesman, who gave his name as Hassan al-Misrati, told Reuters by telephone from the city.
“They are using mortars, a lot of mortars, and they are firing anywhere. They do not care where it lands,” he said. “This crazy man (Gaddafi) has turned hysterical and wants to kill as many people as he can.
“His forces have even attacked the cemetery. What is in the cemetery but dead people? But he doesn’t care,” Misrati said.
Accounts from Misrata cannot be independently verified because the Libyan authorities have not allowed journalists to report freely from the city.
Residents say they and thousands of migrant workers stranded there face shortages of basic foodstuffs, a lack of medical supplies and have only sporadic water and electricity.
Rebels in Misrata, Libya’s third-biggest city about 200 km (130 miles) east of Tripoli, control the Mediterranean Sea port and the northern and eastern districts. Until now they have been under fire from long-range artillery.
But residents say pro-Gaddafi forces, backed by tanks and snipers on rooftops have been able to push gradually into more of the city, and are now using shorter-range mortar fire.
“Because there are few safe areas in Misrata, many families are now living together in the same house,” said Misrati. “Houses are overcrowded and you find at least four of five families together in one house.
“The snipers are on top of 14-storey buildings ... Now they brought the mortars up on to the buildings too, to reach more areas inside Misrata,” he said.
Officials in Tripoli deny targeting civilians but say they are battling armed gangs linked to al Qaeda who are terrorising the civilian population.
Rebels said five people were killed in bombardments on Wednesday and a further 25 were injured.
Misrati said the dead included two children, aged three and five, who were killed when a mortar hit their house. Their sister lost her leg in the blast, he said.
Another rebel spokesman, called Mohamed, said the port was shelled for several hours on Wednesday, forcing it to close temporarily.
With the city surrounded on three sides by pro-Gaddafi forces, the port is the only lifeline. It has been used by aid vessels to bring in food and medicines and evacuate the wounded.
NATO-led Western forces have staged air strikes on pro-Gaddafi targets in Misrata, which they say is part of their United Nations mandate to protect Libyan civilians.
“The coalition bombed the camps of Hamza (brigade) yesterday. The strikes hit the outskirts of the city,” said Mohamed, referring to one of the pro-Gaddafi militias attacking Misrata.
“The brigades stopped their bombardment for fear of coming under new attacks by the coalition,” he said.
But some in Misrata say NATO should be doing more to halt the attacks on the city.
The other rebel spokesman, Misrati, said NATO warplanes targeted a line of 15-20 tanks on Wednesday on the outskirts of Misrata but damaged only one.
“We don’t know how that is,” he said. “NATO does not seem to be efficient. We are very angry with them.”
A spokeswoman at NATO headquarters in Brussels said the alliance would keep up the pace of air strikes, even though pro-Gaddafi forces were moving tanks into residential areas.
“The pace of our operations continues unabated,” the spokesman, Carmen Romero, said on Wednesday. “Misrata is our number one priority.” (Writing by Christian Lowe; Editing by Paul Taylor)