WASHINGTON: Al Qaeda's Afghanistan leader is laying the groundwork to relaunch his war-shattered organisation once the United States and international forces withdraw from the country, as they have warned they will do without a security agreement from the Afghan government, US officials say.

Farouq Al Qahtani Al Qatari has been cementing local ties and bringing in small numbers of experienced militants to train a new generation of fighters, and US military and intelligence officials say they have increased drone and jet missile strikes against him and his followers in the mountainous eastern provinces of Kunar and Nuristan.

The objective is to keep him from restarting the large training camps that once drew hundreds of followers before the US-led war began.

The officials say the counter terrorism campaign a key reason the Obama administration agreed to keep any troops in Afghanistan after 2014 could be jeopardised by the possibility of a total pullout.

House Intelligence Committee Chairman Mike Rogers said the number of Al Qaeda members in Afghanistan has risen but is not much higher than the several hundred or so the US has identified in the past. ''I think most are waiting for the US to fully pull out by 2014,'' he said.

The administration would like to leave up to 10,000 troops in Afghanistan after combat operations end on Dec 31, to continue training Afghan forces and conduct counter terrorism missions.

But without the agreement that would authorize international forces to stay in Afghanistan, President Barack Obama has threatened to pull all troops out, and Nato forces would follow suit.

After talking to Afghan President Hamid Karzai this week, Obama ordered the Pentagon to begin planning for the so-called zero option.

US military and intelligence officials say unless they can continue to fly drones and jets from at least one air base in Afghanistan either Bagram in the north or Jalalabad in the east Al Qahtani and his followers could eventually plan new attacks against US targets, although experts do not consider him one of the most dangerous Al Qaeda leaders.

The officials spoke on condition of anonymity because they were not authorised to discuss publicly the secret counter terrorism campaign or intelligence.

Administration officials have hoped that the US could eventually wind down counter terrorism operations like drone strikes in the region after reducing the Al Qaeda network, leaving local forces in Afghanistan and Pakistan to control the remnants.

But Al Qaeda is not weakened enough yet, and US officials have testified that the inexperienced Afghan forces aren't ready to take over the task unaided.

National Security Council spokeswoman Caitlin Hayden said this week that ''as the possibility of a full withdrawal has grown in Afghanistan,'' the administration was ''undertaking a methodical review of any US capabilities that may be affected and developing strategies to mitigate impacts.''

''The United States will take the steps necessary to combat terrorism and protect our interests,'' she added.

Some administration officials have said Al Qaeda in Afghanistan is less of a threat than when the war began, estimated to be as many as several hundred forced to shelter in the remotest part of the country.

They say Al Qahtani is so remote, he is nearly irrelevant to the larger Al Qaeda movement.

Two US intelligence officials say his group has been so cut off that it has been forced to rely on the Taliban for funding and weapons at times, where it used to be the other way around.

Those officials are far more concerned about Al Qaeda's new offshoots fighting in the Syrian civil war.

''It's really hard to get to New York City from northern Kunar or southern Nuristan'' where Al Qahtani is based, said Douglas Ollivant, a former senior US military adviser in eastern Afghanistan, now with the New American Foundation.

''We do want to keep them bottled up there,'' but he said that's something Afghan forces can do on their own.

''The Afghan forces are not capable of going up there and hunting them, but they are capable of containing them,'' the former US military officer said.

Other experts see Al Qahtani and his kind as the main reason to push for at least a minimal security force in Afghanistan.

''There's an influx of Jihadist groups not massive now active in Afghanistan,'' said Seth Jones of the Washington-based Rand Corp who once worked for US Special Operations Command in Afghanistan.

He listed the most dangerous as Al Qaeda; the Pakistan Taliban; Lashkar-e-Taiba, blamed for the 2008 Mumbai terrorist attacks; and Harkat-ul-Jihad-Al-Islami, which has strong links to Al Qaeda.

''Not having US forces in Afghanistan would embolden these groups and be counterproductive for US national security,'' he said.

Those tracking Al Qahtani say he has survived by following some of the same rules that helped Osama bin Laden avoid capture for so many years: He stays off cellphones and radios to hide from spy satellites and airborne radars, instead using couriers or face-to-face meetings, and he stays on the move.

When he travels to populated areas, he stays among women and children, which he knows the US will avoid striking.

The local tribesmen do not aid the US effort, nor does the barren, mountainous terrain where incoming raiders are visible for miles.

"When helicopters went in, you can hear the whistles go up," from the villages, echoing across the valleys and sending militants fleeing for cover, one of the US military officials said.

The officials say US special operators have all but given up capturing Al Qahtani and have traded fruitless and dangerous helicopter-borne raids for air strikes by drone and jet, averaging three to five a week.

To their knowledge, they have never come close to striking him.

The reports give added ammunition to a comprehensive intelligence analysis on Afghanistan completed in December. The report predicted the country will largely disintegrate along ethnic lines after the US departs, with the central government controlling Kabul and a few other key cities.