The Islamist militants of al-Shabaab, like their al-Qaida allies in nearby Yemen, are being driven out of towns they've held for years by Western-backed regional forces who are closing on the southern port city of Kismayu, al-Shabaab's last big stronghold and its financial hub.

The word is that al-Shabaab, which means "the Youth," is on its last legs after being hammered for months in a three-pronged pincer assault by Ethiopian, Kenyan and other African forces aided by the United States, France and other Western powers.

But, if the tactics the Islamists have used in the past when they've been cornered is anything to go by, it's more likely al-Shabaab fighters, who are linked to al-Qaida, will avoid a set-piece battle and disperse into the countryside and the jungle to fight again another day.

They could also escalate attacks outside Somalia, particularly against neighboring Kenya, which sent troops to root out al-Shabaab last summer, and Uganda, where 79 people were killed in bombings in Kampala during the 2010 World Cup soccer tournament.

On June 10, Kenyan Internal Security Minister George Saioti and his deputy were killed in a helicopter crash outside Nairobi.

The government hasn't disclosed what caused the crash but Saioti, who had been expected to run in the 2013 presidential election, was an outspoken opponent of al-Shabaab which once controlled just about all of central and southern Somalia.

Underlining al-Shabaab's ability to mount operations even when the group's under heavy pressure, gunmen tried to assassinate Somali President Sheik Sharif Ahmed May 29 as his motorcade passed through the Almada region of southern Somalia en route to Mogadishu.

The president, whose ineffectual Western-backed administration is riddled by corruption and clan feuding, was unharmed, but five bodyguards were wounded.

Kenyan naval forces have been shelling Kismayu from the Indian Ocean. But it's not clear when the Kenyan force of several thousand troops with armor and artillery will launch a push on the densely populated city, the second largest in Somalia.

But Brig. Gen. Paul Lokech, commander of the Ugandan troops, says it makes more military sense to first eradicate al-Shabaab in the Shabelle region around Mogadishu.

An African Union peacekeeping force (Amison), which in recent months has swelled from some 9,000 men to 17,000, drove al-Shabaab out of the port city on the Indian Ocean in August 2011 after prolonged fighting.

But diehard Islamists remnants remain, carrying out suicide bombings.

"If you liberate Mogadishu and Shabelle, that's where the bulk of al-Shabaab is," Lokech said. "That's their center of gravity."

After the Islamists were driven out Mogadishu, the Kenyan and Ethiopian columns moved in from the west and the north, while the Amison forces pressed inland from the capital.

In recent weeks, the slow-moving African pincers have seized several al-Shabaab bastions, including the town of Afgoye, 20 miles west of Mogadishu, May 26 and, three days later, the strategic crossroads and commercial center of Afmadow, 60 miles north of Kismayu, opening the way for an attack on that port city.

Afmadow had often served as a meeting place for top al-Shabaab leaders, including Sheik Muktar Robow Abu Mansour, Sheik Hassan Dahir Aweys and American-born Omar Hammammi.

They were among seven members of the group for whom the United States posted rewards of up to $7 million June 6 -- a new front against al-Shabaab as the administration of U.S. President Barack Obama widens its fight against terrorism across Africa.

The Americans are focused in particular on al-Shabaab's "foreign wing" some 250 Arab fighters and groups of Somali-born citizens of the United States, Britain and Europe. Many of these jihadists, including veterans of the wars in Afghanistan, Iraq and Pakistan, would be able to infiltrate the United States and have the skills to operate clandestinely.

Indeed, there are signs these men have been moving north to the semiautonomous region of Puntland and beyond as military pressure mounted on the Islamists.

It's not clear what their purpose is, apart from getting out of the way of the advancing African forces.

But there have been persistent U.S. intelligence reports that al-Shabaab's foreign wing is seeking to join forces with Al-Qaida in the Arabian Peninsula, based in Yemen which lies across the Gulf of Aden from northern Somalia.

That could spell serious trouble.