The military offensive by Kenyan and Ethiopian forces against Islamic al-Shabaab fighters is gearing up for an assault on the Indian Ocean port of Kismayo that's increasingly seen as a key element in a brewing dispute over oil and natural gas.

Kismayo, in southern Somalia near the Kenyan border, is al-Shabaab's most important base, through which it gets its supply of weapons and much of its revenue.

But the strategic value of the city, one of Somalia's three deep-water ports, has swelled in recent months because of the huge oil and gas discoveries off East Africa.

Kenya made its first big strike in March and the discoveries, all the way south to Mozambique, are piling up. Even South Africa is undertaking major seismic testing, hoping to join the region's growing energy boom.

The oil and gas strikes, including some in neighboring Ethiopia, a U.S. ally that's played a prominent role in the 6-year-old war against the Somali Islamists, have raised the strategic context of the conflict to a new level.

On July 6, the Western-backed Transitional Federal Government in Mogadishu, Somalia's war-battered capital, accused neighboring Kenya of illegally awarding offshore oil and gas exploration rights to leading European oil companies in waters claimed by Somalia.

Eni of Italy got three blocks and Total of France got one.

Kenya and Ethiopia, encouraged by the United States, deployed armored columns into Somalia from the south and west in late 2011 to aid the beleaguered TFG crush the Islamists. In recent months, they have pushed al-Shabaab into a southwestern pocket, with Kismayo as its main stronghold.

The dispute over the four exploration blocks is likely to complicate the stampede of oil companies into a region that over the last year or so has become one of the world's hottest energy prospects.

Analyst Jen Alic, reporting for energy Web site OilPrice.com, observed July 15 that Kenya's timing "will be viewed as suspicious in Somalia ...

"It's plausible that Kenya was hoping that its very successful assistance in pushing al-Shabaab out of Mogadishu and a number of other key bases and strongholds would give it carte blanche to act on oil exploration in contested coastal waters."

It's a tricky situation that goes beyond the legal aspects on ownership of these waters.

"Kenya's involvement in southern Somalia was designed to gain the upper hand on offshore oil block concessions that rightfully belong to Somalia as stipulated in the 1982 U.N. Law of the Seas convention," said Abdillahi Mohamud, director of the East African Energy Forum.

That's an international lobby group that seeks to protect Somalia's energy assets from being exploited by other states.

The forum estimates that impoverished Somalia, ravaged by clan warfare since the dictatorship of Siad Mohammed Barre was toppled in 1992, has offshore and onshore oil reserves of 80 billion-100 billion barrels.

"This small nation of 10 million stands to have the fifth largest petroleum reserves in the world, eclipsing heavyweights like the United Arab Emirates, Kuwait and Nigeria," Mohamud noted.

That may well be an overly optimistic estimation. But there's little doubt that the volume of oil and natural gas in the region is vast.

The recoverable gas reserves found off Tanzania and Mozambique since 2010 are estimated to total 100 trillion cubic feet. Exploration companies say the true figure may be more than double that.

The U.S. Geological Survey says East Africa's waters hold more than 440 tcf of recoverable gas reserves, which will transform the region into one of the world's leading gas exporters, primarily to energy-hungry Asia.

The danger is, of course, that the oil and gas strikes off Somalia will end up fueling the Somali conflict, if they haven't already, and possibly even widening it as regional powers vie with each other to control the energy riches.

This could apply to other East African states as well. Ethiopia, for instance, is considered to be sitting on considerable energy reserves.

These looks set to inflame a long-running insurgency against the brutal regime of Prime Minister Meles Zenawi, who took power in 1991 and who is now reported to be in poor health.

Oil discoveries in the Democratic Republic of Congo, a treasure house of mineral riches, are adding fuel to a murderous war waged largely by neighboring states over its resources.