* As many as 600,000 civilians may be caught inside the city
Thousands of Iraqis surged out of western Mosul on Saturday during a lull in heavy fighting in districts around the densely populated Old City where Iraqi forces are facing fierce resistance from Islamic State militants.
Five months into the battle to take Islamic State's last bastion in Iraq, government forces have cleared the east and half of western Mosul, and are now focused on controlling the Old City as well as the strategic al-Nuri Mosque.
As fighting has entered into the narrow alleyways and densely populated parts of the west, more residents are fleeing liberated areas where food and water are scarce, security fragile and where homes are often caught in shelling.
"We have been trapped for 25 days. No water, no food, everyone will die and they will have to pull us from the rubble," said one resident of Bab Jdid district, not giving his name because relatives remained inside Mosul.
Families with elderly relatives and children marched through western Mosul's muddy streets, past buildings pock-marked by bullet and bombs. Some said they had hardly eaten in weeks, scrambling for supplies handed out by a local aid agency.
"It is terrible, Islamic State have destroyed us. There is no food, no bread. There is absolutely nothing," said another resident.
As many as 600,000 civilians may be caught inside the city with the militants.
Iraqi forces cut off Mosul from the remaining territory that Islamic State controls in Iraq and Syria. But even in liberated areas, many prefer to leave the city amid heavy fighting.
Around 255,000 people have been displaced from Mosul and surrounding areas since October, including more than 100,000 since the latest military campaign in western Mosul began on Feb. 19, according to United Nations figures.
The last week has seen the highest level of displacement yet, with 32,000 displaced between March 12 and 15.
Heavy rains and clouds this week restricted air cover and helicopters, slowing the advance of Federal Police and Rapid Response forces who are consolidating positions around the Old City and the al-Nuri Mosque.
"The weather is cloudy and rainy but our forces are advancing toward their targets," Federal Police Major General Haider Dhirgham told reporters at the forward base inside Mosul. "In a few steps and strikes we will reach the Nuri mosque."
As militants retreat into the confined streets of the Old City, Islamic State has been resisting with snipers, mortars and the armoured suicide car bombs that plough into army positions.
The fall of Mosul would be a significant blow to Islamic State, whose leader Abu Bakr al-Baghdadi used the al-Nuri mosque to declare a self-proclaimed caliphate spanning Iraq and Syria in 2014.
US officials have estimated that around 2,000 fighters remain inside the city. But even after the liberation of Mosul, there are risks that militants will return to the kind of guerrilla warfare and bombings they have used in the past.
Macron leads field of 11 candidates in French election
* Constitutional Court declares list of candidates for 1st round
* Latest poll shows Macron remains best placed to win run-off
* Macron calls for youth military service (Adds poll, Macron army plan, Melenchon march, airport incident)
By John Irish and Gus Trompiz
PARIS, March 18 (Reuters) - Eleven candidates got the go-ahead on Saturday to run in France's presidential election in a vote that independent centrist Emmanuel Macron remains favourite to win.
French voters go the polls on April 23 and May 7 in the two-round election, which is being closely followed outside France as another test of popular discontent with traditional parties and institutions like the European Union.
The campaign has been highly unpredictable, dominated by a fraud investigation into conservative Francois Fillon, which has cost him his place as election front-runner.
French voters will have a choice of 11 candidates after the country's Constitutional Council announced the list of contenders that had met conditions to stand.
In addition to leading candidates Macron, Fillon and far-right leader Marine Le Pen, the list included three candidates who passed the threshold of 500 elected officials just in time: Jacques Cheminade and Philippe Poutou of small far-left parties and centrist lawmaker Jean Lasalle.
The expiry of the deadline would put paid to any further attempts by members of the conservative Republicans party to seek an alternative candidate to Fillon, who is being investigated on suspicion of misusing public funds to pay his wife and children and over a gift of expensive suits.
A BVA poll for Orange released on Saturday showed Macron was best placed to win. He was second in first-round voting intentions, a point behind the National Front's Le Pen who had 26 percent, but would win a run-off against his far-right opponent 62-38, according to the survey.
Fillon has slipped to third in the polls, recording 19.5 percent in the BVA survey, suggesting he would fail to reach the run-off.
Benoit Hamon, the ruling Socialist party's candidate, ranked fourth with 12.5 percent, the poll showed, only slightly ahead of radical left-wing contender Jean-Luc Melenchon.
Several thousand supporters cheered Melenchon on Saturday at a central Paris rally billed as a show of force after he spurned Hamon's overtures to join him.
The left's divisions have favoured the emergence of Macron, a 39-year-old former economy minister of incumbent Socialist President Francois Hollande.
Macron on Saturday said he wanted to restore military service to France for some 600,000 young people each year as part of efforts to face a world entering an era of "turbulence" comparable to the Cold War.
The shooting of a man who attacked a soldier at Paris Orly airport on Saturday refocused attention on security, a major concern after a series of attacks by Islamist militants.
Le Pen blames immigration and shortcomings in the EU for contributing to security risks, and has promised to take France out of the euro zone and hold a referendum on its EU membership.
Her popularity has been a concern for international investors, and a rise in her ratings in another poll on Friday pushed the euro lower.
