Updated, 7:10 p.m.

Mali's rebels are adapting to attacks from above as the 15-day-old air war over West Africa gets a lot more intense. After Paris' air force last week blasted the militants' exposed vehicles and headquarters buildings (depicted in the targeting system video above), the survivors of the initial bombing runs learned to camouflage themselves.

"The rebels will quickly adapt their tactics to better conceal themselves and thus complicate targeting from the air," Christopher Chivvis, an analyst with the California-based think thank RAND, said on Thursday.

More complicated targeting is forcing the French-led coalition to add spy planes to its order of battle. "There's still more need for [intelligence, surveillance and reconnaissance] platforms," David Cenciotti, a highly-regarded aviation journalist, tells Danger Room. "You must detect and follow rebels as they move, then you can order, coordinate and manage air strikes."

“It’s tough to get access for platforms that can collect," warned Army Gen. Carter Ham, in charge of U.S. Africa Command. But that doesn't mean the French and others won't try.

The aerial escalation has driven the expansion of the French-led coalition from just a handful of countries to more than a dozen. Nigerian and British combat planes and airlifters from several European and Middle Eastern states have joined the French aerial armada hunting militants in northern Mali. There have also been unconfirmed rumors of greater American involvement in the airborne onslaught.

In the first phase of the air war starting Jan. 11, French Gazelle and Tiger helicopters and Mirage 2000 and Rafale fighter-bombers based in Mali, Chad and France pounded rebel ground forces, supply lines and command infrastructure, while two French Harfang drones spotted targets. French KC-135 tankers refueled the fighters as French, British, Canadian, Belgian and Danish and chartered Ukrainian cargo planes hauled reinforcements, armored vehicles and supplies into Bamako, Mali's capital.

The more intensive second phase of the aerial campaign around a week later saw the U.S. offer up C-17 transports. The Nigerians added transports, Hind helicopter gunships and a pair of Alpha Jet light bombers. Italy, Germany, Spain, The Netherlands and the UAE joined the airlift effort and Italy sent a KC-767 tanker to boost the French KC-135s.

But the most striking additions were the spy planes, demand for which is apparently increasing fast. The French deployed to Senegal five Atlantique II naval patrol planes, which are optimized for hunting ships and subs but can also use their video cameras to spot land targets. And the British Royal Air Force has committed one of its five Sentinels, business jets fitted with powerful underslung radars for simultaneously tracking scores of ground targets. "It could provide French forces with data relating to the rebels' movements," Cenciotti explains.

The Sentinel could be just the beginning for the RAF in Mali. U.K. Defense Secretary Phillip Hammond said London "would be looking at further French requests for additional logistical and surveillance support."

The details of America's participation in the Mali air war are less clear, although Washington has expressed its determination to help in some capacity. "We are in for a struggle, but it is a necessary struggle," Secretary of State Hillary Clinton said Wednesday. "We cannot permit northern Mali to become a safe haven."

But the Pentagon has copped only to sending five C-17s. But there have been rumors of U.S. drones and other surveillance and strike aircraft in the region. "MQ-1 [Predator] and RQ-4 [Global Hawk drones] can be heard two or three days a weak crossing the Maltese airspace towards North Africa using LiveATC.net," a Website that picks up air traffic control radio broadcasts, says Cenciotti. The robots could be Mali-bound.

Moreover, an air strike in northern Mali in June might have been a Predator's handiwork. And according to The Washington Post, U.S. Special Operations Command has based PC-12 manned spy planes (also known as U-28s) in Burkina Faso for patrols over West Africa, possibly including Mali.

Late Saturday, the Pentagon told reporters that Defense Secretary Leon Panetta committed to conducting midair refueling missions for French jets, something the French have sought from the U.S. since their war began. The U.S. will also transport African troops, particularly those from Togo and Chad, to the battle. It's another gradual escalation of the U.S. contribution to its ally's "aggressive operations against terrorist networks in Mali," as Panetta's spokesman, George Little, put it.

With or without the Americans, the growing number of warplanes supporting the French-led ground war points to a more intensive, potentially bloodier intervention. If America's own wars across Africa, the Middle East and Central Asia are any indication, it's a lot easier to increase a military commitment than to decrease one. That could point to a drawn-out campaign for France and its allies.