* Demand for illegal guns climbs; AK-47 price triples
* Fears mount over prospect of Taliban return, civil war
* President dismisses chaos fears once West pulls out
* Unrest post-2014 a threat to foreign investment
By Martin Petty
KABUL, Dec 18 (Reuters) - Afghan father-of-four Mohammad Nasir has a secret he's been keeping from his family.
The aid worker pulls a television bench out from the living-room wall of his Kabul home. Behind it is a carved out shelf, hiding what he hopes will keep loved ones safe when Western troops withdraw by the end of 2014 -- an AK-47 assault rifle.
Arms purchases are soaring in Afghanistan, along with the price of weapons, a sign that many Afghans fear a return of the Taliban, civil war or rising lawlessness.
An assault rifle cost $400 a year ago. Today, some arms dealers are selling them for triple the price.
And it's not just ordinary Afghans who are buying. Warlords who control militias, and former anti-Soviet mujahideen fighters are also boosting the trade.
"Whenever you turn on the TV or radio, the discussion is 2014. I'm not feeling safe now, it's become like doomsday for Afghans," said Nasir, 48, storing the polished second-hand rifle and slamming the TV unit back against the wall.
"People are saying security will collapse, or soldiers will join warlords or the Taliban, so we need something to protect our families when there's a crisis."
The brisk arms business is complicating the government's efforts to pacify a country where the Taliban can strike virtually anywhere, ethnic tensions can easily ignite violence, and warlords are constantly jockeying for influence.
Afghanistan wants to project an image of stability ahead of 2014, a critical year when presidential elections will be held and the 350,000 Afghan security force will take over security.
Any upheaval could also encourage regional powers like Iran and Pakistan to try and gain influence before the Afghan endgame, a widespread fear among officials and ordinary Afghans.
President Hamid Karzai calls the talk of chaos, Western media "propaganda", and says Afghan security forces have made great progress.
But for many Afghans, the threat of a descent into chaos is real so a growing number are investing in weapons, despite exorbitant costs. The average Afghan family earns only about $200 a month.
Reuters spoke to buyers and sellers of illegal arms in five provinces and each cited the foreign troop withdrawal as the main driver of the underground trade.
"More people are buying weapons now, some to protect themselves from kidnappers and robbers and others in anticipation of things getting worse," said a Kabul resident in his fruit shop, where a verse from the Koran on the wall calls for God to guide Muslims on a straight path.
He bought a handgun illegally for $500, a model his dealer says now fetches $1,000.
"If the situation changes in 2014 this area will once again become a battlefield between former warlords who are still powerful," he said.
The government has highlighted 2014 as a year to invest in Afghanistan, which has relied on foreign aid for its economic lifeline, and take advantage of its cheap labour and land leases. Last month it held a televised conference promoting the country's natural resources and its industrial potential.
In the 10 years following 2014, the government hopes revenues from oil, natural gas, iron, copper and other mining ventures will generate $4 billion in annual revenue.
But in the north, which is home to untapped oil and gas resources, warlords and their supporters are now re-arming for fear militants may seize power again, say residents.
Afghanistan's largest foreign investment project, the Aynak copper deposit in Logar province, lies in one of the country's most dangerous regions just south of the capital, Kabul.
Rocket attacks this year saw its Chinese workers temporarily flee the project, which is run by China Metallurgical Group (MCC) and Jiangxi Copper.
Afghanistan has seen little peace in three decades. The American-backed mujahideen drove out the Russians in 1989 after 10 years of occupation, but American interest faded quickly.
Much of Kabul was later destroyed in a civil war and more than 50,000 civilians killed. The Taliban rose from the ashes of that conflict and imposed their austere brand of Islam.
Afghans fear they will be abandoned by the United States once again. Most don't want the Taliban to return, so they are determined to protect themselves.
And there are plenty of weapons; arms left over from the war against the Soviets, guns smuggled over the porous border with Pakistan and those sold by former mujahideen commanders.
Russian or Pakistani-made AK-47 assault rifles are the biggest sellers, followed by light machineguns. In some areas, the militias go for rocket-propelled grenades.
To avoid arrest, arms dealers and sellers operate by word of mouth, avoiding cellphones which may be tapped by authorities. Deals are sealed in restaurants, homes or busy street markets.
Afghan authorities say they've had success in seizures of illegal firearms but concede that in a country with a turbulent history, their efforts may have little impact.
The government was deeply embarrassed when Energy and Water Minister Ismail Khan, an influential former warlord, recently called on militias to rearm to protect Afghanistan after 2014.
General Mohammed Najib Aman, a deputy of the anti-terrorism department at the Interior Ministry, denies the illegal gun trade is flourishing.
"Buying and selling of weapon, without being authorized, is...illegal and they will be arrested," Aman told Reuters.
The government is encouraging people to seek licenses for weapons so the authorities can track guns. Aman estimates between 30,000 and 40,000 gun licenses have been issued.
But the positive message from the government and NATO-led force runs counter to the unease on the streets, where the Afghan security force has gained little public confidence.
"In my area there are lots of kidnappings, robbery and other criminal activities and also lots of fear of 2014," said Shir Ali, speaking in his pharmacy in northern Kunduz Province. "I bought this very expensive Kalashnikov to protest my family."
At least 57 foreign troops have been killed by rogue Afghan security personnel this year. That figure represents about 13 percent of ISAF deaths in Afghanistan in 2012.
Lieutenant General James Terry, deputy commander of U.S. forces in Afghanistan, said the country's "gun culture" was partly to blame.
"This is a society that's really been traumatized by 30-plus years of war," Terry said. "We also understand that a lot of grievances and dispute resolutions are done, frankly, at the barrel of a gun."
Former mujahideen commanders in particular are cashing-in on the insecurity, using their wartime connections to acquire handguns and rifles and sell at inflated prices.
Islamuddin laid down his weapons after the Taliban was ousted in 2001, and became a used car salesman. These days that's a front for his real money-making business.
He now sells light machine guns for 150,000 Afghanis ($2,900), double the value a year ago, and AK-47s for 60,000 Afghanis ($1,150), triple that of last year.
"People are worried, so they're buying guns now because they might not be able to buy one when they most need it," he said sitting in a hotel restaurant.
Militias also look to be heeding Ismail Khan's call to arms.
"The number of sales and the price of guns has gone up and former mujahideen commanders who served warlords are buying more and more from us every day," said one seller. "They're anticipating civil war once the foreign troops leave."
Not all Afghans expect a war. Waheed Mujhda, a politics expert at the Afghan Analytical and Advisory Centre, said even warlords realised renewed civil conflict would not help anyone.
"Having so many people owning guns is a big problem for the government, but it's not a political problem," he said. "There may be small conflicts after 2014, but civil war is unlikely. The last time, it was a failure that no one wants to see again."
But a growing number of people are not taking any chances.
"I'm sure if something goes wrong in 2014, I'll face lots of problems," said Nasir. "If the Taliban return to power they'll kill me because I work with the government. If warlords come to power it's bad news for everyone." (Additional reporting by Folad Hamdard in KUNDUZ and David Alexander in WASHINGTON; Editing by Michael Georgy and Michael Perry)