The U.S. deployment of 200 Marines to a naval base in Sicily for possible operations in Libya, a short hop across the Mediterranean, underlines how the Americans have been building a network of bases in Italy as launch pads for military interventions in Africa and the Mideast.

The signs are that 20 years after the American military's first, and costly, encounter with Muslim militants in Mogadishu, Somalia, U.S. operations in Africa are growing as the Islamist threat expands.

Another key factor is U.S. President Barack Obama's switch in his counter-terror strategy from drone strikes against al-Qaida to pinpoint raids by small Special Forces teams, as seen in Somalia and Libya Oct. 5.

These were triggered by Islamist violence in both countries, including the Sept. 21 seizure of the Westgate shopping mall inl Nairobi, capital of Kenya, by fighters of Somalia's al-Qaida affiliate, al-Shabaab, that left at least 67 people dead.

The U.S. SEAL Team 6 seaborne raid on the Somali coastal town of Barawe to capture al-Shabaab mastermind Abdulkadir Mohamed Abdulkadir,a Kenyan of Somalia origin, ran into heavier than expected resistance and had to be aborted.

But the U.S. Army's Delta Force had more success in its raid on Tripoli when they grabbed longtime al-Qaida fugitive Nazih Abdul-Hamed al-Ruqai, aka Abu Anas al-Libi, indicted by a U.S. court in 2000 for the August 1988 bombings of U.S. embassies in Nairobi and Dar es Salaam, Tanzania, that killed 224 people.

These raids reflect a U.S. move away from the kind of risk-averse operations the Americans have been mounting with missile-firing drones to on-the-ground raids against high-value targets.

The abhorrence of risk stemmed largely from of the psychological fallout over the October 1993 operation in Mogadishu to capture Somali warlord Mohamed Farah Aidid that went badly wrong and led to the downing of two U.S. helicopters and the deaths of 18 Rangers and Special Forces troopers.

U.S. President Barack Obama's visit to Africa in June-July was widely seen as evidence of the White House's broader foreign policy objectives which have included an expansion of U.S. military operations across Africa.

Many of these involve small-scale "secret wars" against Islamists, mainly linked to al-Qaida and often carried out under the aegis of the U.S. Africa Command established in 2007.

"Both the number and complexity of U.S. military operations in Africa will continue to grow in the medium term," observed Oxford Analytica.

"Given the relatively high impact contribution they make to Washington's strategic goals, such military operations will also increasingly encroach on domains traditionally associated with development and diplomacy.

"However, they will also increasingly commit the United States to an 'intervention-led' foreign policy in Africa."

Although Africom and the U.S. Joint Special Operations Command claim they have a small footprint in Africa, over the last year or so they've been increasingly active in building up a U.S. military presence -- and especially reach -- across the continent.

The United States has only one official base in Africa, the counter-terrorism facility at Camp Lemonnier, a former French Foreign Legion base in Djibouti, East Africa, where Special Forces, strike jets and armed unmanned aerial vehicles are based.

But small units are deployed across Africa. Meantime, the Americans have established a network of bases in Italy, involving a significant manpower shift southward from the old Cold War bastion of Germany.

The Marines moved to Italy from Spain this month are the vanguard of a larger force dubbed Special Purpose Marine Air-Ground Task Force-Crisis Response.

It was established after the Sept. 11, 2012, attack on the U.S. consulate in Benghazi, Libya, in which U.S. Ambassador Christopher Stevens and three other Americans were killed.

According to U.S. security specialist David Vine, the Pentagon has spent around $2 billion -- and that's just construction costs -- "shifting its European center of gravity south from Germany" and transforming Italy "into a launching pad for future wars in Africa, the Middle East and beyond."

The U.S. Marines are being moved to the Naval Air Station at Sigonella on Sicily, which will eventually have a force of 1,000 Marines with its main focus Libya, 100 miles across the Med.

Vines estimates there are now 13,000 U.S. troops in Italy at Sigonella and some 50 other facilities like Vicenza, a former Italian air force base near Venice, with the 173rd Infantry Brigade Combat Team (Airborne), a rapid response force.