The Obama administration is intensifying its campaign against an al-Qaeda affiliate in Somalia by boosting the number of proxy forces in the war-torn country, expanding drone operations and strengthening military partnerships throughout the region.

In many ways, the American role in the long-running conflict in Somalia is shaping up as the opposite of the wars in Iraq and Afghanistan: relatively inexpensive, with limited or hidden U.S. footprints.

While the White House has embraced the strategy as a model for dealing with failed states or places inherently hostile to an American presence, the indirect approach carries risks. Chief among them is a lack of control over the proxy forces from Uganda, Burundi and Somalia, as well as other regional partners that Washington has courted and financed in recent years.

All told, the United States has spent more than $500 million since 2007 to train and equip East African forces in an attempt to fight terrorism and bring a measure of stability to Somalia.

Kenya, for example, sent thousands of troops into Somalia last month to fight al-Shabab, a militia affiliated with al-Qaeda, despite U.S. concerns that the invasion could backfire and further destabilize a country ravaged by two decades of civil war.

This week, Ethi­o­pia sent its own, smaller force across the border, according to Somalis. The Ethio­pian government has denied these reports but acknowledged that it is considering a military offensive.­­­­­

These operations are reviving painful memories of an Ethio­pian invasion in 2006 that was backed by U.S. forces and preceded by an extensive CIA operation. In that case, the Ethio­pian army — with some U.S. air support — rolled into Somalia to oust a fundamentalist Muslim movement that had taken over Mogadishu, the capital. But the Ethiopians eventually withdrew after they became bogged down by a Somali insurgency.

“That effort was not universally successful and led, in fact, to the rise of al-Shabab after [Ethiopia] pulled out,” Johnnie Carson, the assistant secretary of state for African affairs, told reporters Tuesday.

Al-Shabab, which means “the youth” in Arabic, has imposed a harsh version of Islamic law in parts of Somalia and organized attacks elsewhere in East Africa, including suicide bombings and kidnappings in Uganda and Kenya. While some foreign radicals — including Somali Americans — have joined the group’s ranks, U.S. counterterrorism officials say the movement is divided between those who share al-Qaeda’s global aims and others who want to confine their actions to Somalia.

The Obama administration has not directly criticized Kenya or Ethi­o­pia for entering Somalia, saying it is legitimate for both countries to defend themselves against al-Shabab attacks on their territory. But the administration has urged both to withdraw as soon as possible and instead help expand a 9,000-member African Union peacekeeping force in Mogadishu that is composed of U.S.-trained troops from Uganda and Burundi.

“We have always been very cautious, prudent, concerned about the neighbors getting involved,” said a senior U.S. defense official, who spoke on the condition of anonymity under ground rules set by the Pentagon.

Millions in U.S. support

Over the past four years, the State Department has provided $258 million for the African Union peacekeepers in Mogadishu. The Pentagon is spending $45 million this year alone to train and equip the force with body armor, night-vision equipment, armored bulldozers and small tactical surveillance drones.

In addition, the Pentagon this year has authorized $30 million to upgrade helicopters and small surveillance aircraft for two countries that border Somalia: Djibouti and Kenya.

The subsidies underpin the Obama administration’s strategy of building up regional forces so they can fight al-Shabab directly, while minimizing any visible role for U.S. troops. Mindful of the 1993 “Black Hawk Down” debacle, in which two U.S. military helicopters were shot down in Mogadishu and 18 Americans killed, the Obama administration has steadfastly avoided deploying soldiers to Somalia, save for small clandestine missions carried out by Special Operations forces.

Instead, the U.S. military has gradually established a stronger presence around Somalia’s perimeter.

To the north, in Djibouti, a small country on the Horn of Africa, about 3,000 American troops are stationed at Camp Lemonnier, the only permanent U.S. military base on the continent. Many are engaged in civil-affairs and training programs throughout East Africa, but the camp is also home to a fleet of unmanned Predator drones and Special Operations units that conduct Somalia-related missions.

To the south, the U.S. military has a smaller but long-standing presence at Manda Bay, a Kenyan naval base about 50 miles from the Somali border. For several years, Navy SEALs have trained Kenyan patrols on the lookout for Somali pirates.

Other U.S. forces have helped the Kenyan army train a 300-man Ranger Strike Force and a battalion of special operations forces with about 900 personnel, according to a U.S. diplomatic cable obtained by the anti-secrecy group WikiLeaks.

Even after years of American assistance, the Kenyan armed forces still have much to learn, acknowledged another senior U.S. defense official involved in the training.

“It’s not for the faint of heart,” the official said, speaking on the condition of anonymity to give a frank assessment. “It is tough. It’s time-consuming. But from a relative standpoint, it’s inexpensive.

“I’m not saying, ‘Do things on the cheap.’ But we accomplish two things: We create regional stability, and we don’t have large U.S. deployments.”

Kenya’s mission

Kenya sent about 2,000 troops into southern Somalia last month to attack al-Shabab. Two senior U.S. defense officials said they did not know if any of those Kenyan forces had received U.S training. Maj. Emmanuel Chirchir, a Kenyan military spokesman, declined to comment.

Obama administration officials said that they did not encourage Kenya to take military action and that the United States was not involved in the fighting in Somalia. Chirchir said Washington was providing “technical support,” but he would not elaborate. U.S. officials declined to comment.

Roba Sharamo, the head of the Institute for Security Studies in Nairobi, said the United States may be sharing satellite imagery and other intelligence with Kenya. “Because of the political sensitivities around Somalia, the U.S. can’t necessarily say, ‘We are involved,’ ” he said.

Meanwhile, the United States has stepped up its aerial surveillance of Somalia. The Air Force is flying Reaper drones from the Seychelles, a tropical archipelago in the Indian Ocean, and from a newly expanded civilian airport in Arba Minch, Ethi­o­pia.

The Reapers can be armed with Hellfire missiles and satellite-guided bombs. U.S. officials have said the Ethiopia-based drones are being used only for surveillance, not airstrikes.

But they have been vague about whether the drones flying from other regional bases are armed. Part of the reason is to sow confusion in the minds of al-Shabab fighters, said Army Gen. Carter F. Ham, the head of the U.S. Africa Command. The military has sporadically conducted drone airstrikes in Somalia but without public acknowledgment.

“I like it a lot that al-Shabab doesn’t know where we are, when we’re flying, what we’re doing and specifically not doing,” Ham said in an interview. “That element of doubt in the mind of a terrorist organization is helpful, not just to us but to the Somali people.”

Peacekeepers’ victory

Since 2007, the United States has been the primary backer of the African Union peacekeeping force in Mogadishu. The contingent is composed entirely of soldiers from Uganda and Burundi, most of whom were trained by U.S. contractors or American military advisers.

The peacekeepers struggled for years to secure a foothold in Somalia but achieved a breakthrough three months ago when they chased al-Shabab fighters out of most of Mogadishu. The African Union force, however, is largely confined to the capital.

Some African countries are pushing for a rapid expansion of the peacekeeping force, more than doubling its size to 20,000 troops, but it’s unclear that the United States is prepared to underwrite such growth.

“I don’t see any increase,” said a senior State Department official, who spoke on the condition of anonymity. “We’re already at a very high level.”

The United States has also been a primary backer of indigenous security forces loyal to Somalia’s Transitional Federal Government, contributing $85 million since 2007. Those forces, however, have been plagued by desertion and poor health and are widely seen as ineffective.

Analysts said that no matter how much the Obama administration invests in proxy or Somali security forces, it won’t be able to ease Somalia’s chronic instability without a political solution involving its many clans.

“The political track isn’t there to push back an insurgency,” said J. Peter Pham, director of the Atlantic Council’s Michael S. Ansari Africa Center. Even if the Kenyan, Ethiopian and African Union troops rolled up military victories against al-Shabab, he predicted, the Islamist movement would eventually return in some form.

“It’s like the tide coming back,” Pham said.

Special correspondent Alice Klein in Nairobi contributed to this report.