Q+A: What is fate of civilians in Sri Lanka's war?

COLOMBO (Reuters) -- Civilians who escaped Sri Lanka's war zone this week said Tamil Tiger rebels shot at them while they tried to flee fighting as the military attempts to finish off the separatist group and end a 25-year civil war.

Here are some questions and answers about the civilians' situation:

HOW MANY ARE TRAPPED?

The United Nations and the International Committee of the Red Cross say around 250,000 people, nearly all Tamils, are trapped by the fighting in the north. The government says the figure is about half of that. The United Nations on Tuesday said it was preparing for an exodus of 150,000.

Already, dozens of aid workers are pouring into Vavuniya, a north-central town where many refugees are brought.

HOW MANY HAVE ESCAPED THE FIGHTING?

According to the military, more than 32,000 as of Thursday. Nearly all have escaped in the last week, when the rate of people fleeing jumped sharply.

WHAT KIND OF RISKS DO THEY FACE?

They must run a gauntlet between the Sri Lankan armed forces and Liberation Tigers of Tamil Eelam (LTTE) fighters who have been trading artillery fire. Now, witnesses say the Tigers fired at those who tried to flee. The northeastern jungles they have to get through are laden with booby traps and mines. Some civilians who escaped were blown up or wounded by a suspected LTTE suicide bomber on Monday at a center where the military registers refugees. The LTTE denied responsibility.

HOW MANY HAVE BEEN KILLED OR WOUNDED?

The ICRC, the only aid agency with a permanent presence in the war zone, has said hundreds have been killed and injured in the past few weeks, but has not given an exact figure -- save saying that 16 more were killed on Monday. Witnesses who escaped say 10-15 people were dying daily where they were.

The government says the overall figures are inflated, but blames the Tigers for killing at least 27 in the last week alone. The pro-rebel TamilNet website on Wednesday quoted an LTTE political official as saying thousands had been killed, but he cited no source. Verifying any account is next to impossible in a war zone sealed off to independent observers.

WHY HAVEN'T MORE FLED?

Human Rights Watch, aid agencies and the government have said the Tigers have forced people to stay at gunpoint, and are using them to fight, build defenses or act as human shields. The Tigers, who for years have had a policy of making every family hand over one person to fight, deny that. They say the people are staying of their own free will and fear government persecution at army-guarded refugee camps.

WHAT IS BEING DONE ABOUT THEM?

The Sri Lankan army said on Thursday it has set up a new 12 km (7 mile) long no-fire zone on the coast north of the port of Mullaittivu, to replace an older one inland. The LTTE and government had traded accusations of firing inside the old one.

The Tigers have not answered the military's accusation that they moved their heavy weapons near populated areas and hospitals. Diplomats and aid agencies are applying heavy pressure on both sides not to fire near civilians. The United Nations and ICRC are working hard at getting convoys to bring aid in and people out, but have been frustrated in most efforts.

WHY ARE AID AGENCIES HAVING TROUBLE?

The United Nations and ICRC require permission and guarantees of safe passage from both sides. The government last year ordered most aid agencies out of the war zone but has facilitated aid convoys with U.N. and ICRC help and promised safe passage.

The United Nations last month said the military stopped firing to allow a medical convoy to leave, but the Tigers then refused to let it go. The U.N. also said the Tigers stopped its local staff and their families from leaving on a convoy, which the U.N. protested was a violation of international humanitarian law.

(Editing by Alex Richardson and Jerry Norton)