KABUL—An American proposal to cut the size of Afghan security forces by more than one-third after 2014 could lead to a catastrophe, Afghanistan´s defense minister told The Wall Street Journal, underlining his government´s growing fears of being abandoned after most foreign troops withdraw.

The minister, Gen. Abdul Rahim Wardak, expressed his concerns after the U.S., which along with its allies funds Afghanistan´s military and police forces, circulated a new proposal to cut troops to 230,000 after 2014, from 352,000 this year.

That proposed troop reduction, discussed at a North Atlantic Treaty Organization ministerial meeting in Brussels, was confirmed in an interview by U.S. Army Lt. Gen. Daniel Bolger, commander of the NATO Training Mission-Afghanistan that developed it.

The smaller Afghan force, estimated to cost some $4.1 billion a year, reflects "our assessment of what the international community will provide and what the Afghans can provide for themselves," Gen. Bolger said.

The Afghan government is still negotiating with the U.S. over what kind of American military presence, if any, will remain in the country after that deadline. With most of the U.S.-led coalition forces scheduled to leave Afghanistan by late 2014, a robust Afghan army and police will be needed to keep the Taliban insurgency at bay, Afghan leaders and some American lawmakers say.

"Nobody at this moment, based on any type of analysis, can predict what will be the security situation in 2014. That´s unpredictable," Gen. Wardak said. "Going lower [in Afghan troop numbers] has to be based on realities on the ground. Otherwise it will be a disaster, it will be a catastrophe, putting at risk all that we have accomplished together with so much sacrifice in blood and treasure."

Many NATO allies have long opposed the American drive to ramp up the size of the Afghan army and police, saying that the Afghan economy simply cannot afford such an expensive professional military. The Afghan forces are expected to meet their target of 352,000 personnel, scheduled for October, months ahead of time.

The recent proposal to cut the force´s size after 2014 has been produced by a "U.S.-only planning team," and does not yet reflect an agreed position of the allied governments, Gen. Bolger said.

The U.S. is now spending some $11.2 billion a year on Afghan security forces—well above the Afghan government´s annual budget. The Obama administration´s request for fiscal 2013 is $5.7 billion.

U.S. Defense Secretary Leon Panetta, speaking to reporters before the Brussels meeting, said the size of the future Afghan force will largely depend on "the funds that are going to be put on the table." The U.S. is looking for additional contributions from countries outside NATO, such as Japan, South Korea, Sweden, and Arab Gulf monarchies.

America´s European allies, gripped by economic problems at home, are particularly reluctant to meet U.S. requests to fund a significant part of the $4.1 billion price tag estimated for the years after 2014, with some pressing for an even leaner Afghan force.

"The Americans didn´t ask our advice when they were building it up, and now all of a sudden they want us to pay up," one diplomat from a NATO country said.

U.S. officials stressed Friday that the number remains a subject of debate both among U.S. officials and between U.S. and NATO officials.

"There is an awful lot in play," said a U.S. military officer. "There are 10 American opinions, 10 German opinions, 10 French opinions.... You are hearing the normal give and take."

U.S. and Afghan officials say they expect the issue to be settled by a NATO summit in Chicago in May.

Gen. Wardak has long campaigned for an even larger force than that currently envisioned, saying that implementing a successful counter- insurgency strategy would require between 400,000 and 500,000 troops. He said he now realizes he won´t get that number.

"We are becoming victim to a lot of issues—economic austerity, the war has been prolonged beyond the expectations… elections in countries where we are becoming hostage to local political agendas," Gen. Wardak said.

Afghan officials aren´t just worried by the manpower levels. They also say the Afghan army badly needs the "enablers"—such as medevac, intelligence, surveillance and airlift assets—that are currently provided by NATO.

"At the moment these forces are built as lighter-than-light infantry," Gen. Wardak said. "They don´t have all the capabilities that a modern army in any country has."

It is possible that a force of 230,000 would be sufficient if the security situation improves, the Taliban embrace the tentative peace process with Kabul, and Pakistan shuts down insurgent safe havens on its soil, Gen. Wardak said.

"If it happens the question of numbers will be less relevant," he said. "But if it doesn´t then all that we are planning will be in danger. We have to leave some level of flexibility."

Gen. Bolger said that the U.S. and allies recognize Afghan concerns. "Three years is a long time. We´ll want to look at the security situation in the country, we´ll want to look at what arrangements Afghanistan has made with other countries," he said. "We haven´t figured any of that out yet."

He added that NATO hasn´t determined whether any planned drawdown of Afghan forces would start on Jan. 1, 2015, or on a different date.

Retired U.S. Lt. Gen. David Barno, a senior adviser at the Center for a New American Security think-tank and a former commander of coalition forces in Afghanistan, cautioned about the need to weigh the fiscal constraints against the perils of cutting the Afghan forces too deeply. "The risk here is you are going to reduce funding for Afghan security forces in the midst of a robust insurgency," he said. "Leaders have to be careful they do not get seized with the affordability argument without understanding the military implications."

Sen. Lindsey Graham (R., S.C.), a member of the Senate Armed Services Committee and an influential voice on Afghanistan policy, said he believed that cutting the Afghan forces to 230,000 "does not seem wise."

"I would hate to be the senator who tried to end this on the cheap. … If we fail to deliver it will be a huge blunder that haunts our country," he said. "If the country goes back to Taliban control it will all be for nothing."

With attrition rates in the Afghan army running at 1.4% a month, the proposed drawdown could be achieved—at least in part—without the mandatory dismissals that could fuel the insurgency with an influx of resentful, trained ex-soldiers.

In Iraq in 2003, an American decision to disband the Iraqi army helped spark an insurgency that has yet to be extinguished.

"Immediate downsizing of 130,000 people in a country like Afghanistan, where these people are providing livelihood to at least a million people, will have very risky consequences," Gen. Wardak warned. "It has to be gradual," Gen. Bolger agreed.

Afghan leaders, many of them—like Gen. Wardak—drawn among U.S.-backed anti-Soviet mujahedeen commanders, still have painful memories of how the U.S. turned away from Afghanistan after the Soviet Union´s collapse in 1991, a disengagement that plunged the country into a civil war and ultimately led to the rise of the Taliban and al Qaeda.

"I do hope the international community has learned from their experience in the 1990s," Gen. Wardak said. "This country is located in one of the most dangerous neighborhoods in the world, and there are lots of threats."

—Julian E. Barnes, Adam Entous and Matt Murray contributed to this article. (Copyright © Dow Jones & Company, Inc.) 02/18/12)