Islamist fighters linked to al-Qaida are reported to be moving into the semi-autonomous region of Puntland in northeastern Somalia where Western companies recently struck oil in fields believed to hold more than 1 billion barrels of crude.

As a new oil conflict brews in the desert wastes of a little-known statelet in the forbidding Horn of Africa, Vancouver wildcatter Africa Oil, which made the strike in the Dharoor block, is stepping up security and preparing for trouble.

Al-Qaida leader Ayman al-Zawahiri declared Feb. 9 that al-Shabaab, the main Islamist group in Somalia currently locked in a multi-front battle against U.S.-backed African Union forces supporting the shaky Western-backed Transitional Federal Government, has joined forces with the jihadist movement.

Soon after, al-Shabaab began sending Internet and Twitter warnings that "Somali oil carries death."

In what's seen as the first move in an armed campaign against Western oil and companies operating in impoverished Puntland, a self-declared autonomous state since 1998, al-Shabaab has said it refuses to recognize exploration licenses issued by the regional authority.

On March 3, at least nine people were killed when militants attacked a Puntland security checkpoint near the commercial center of Bosasso. This was apparently carried out by Puntland Islamists known as the Mujahedin of the Golis Mountains, a region in the enclave's north.

Their leader, Yassin Khalid Uthman, declared the group has joined al-Shabaab and pledged loyalty to its leader, Sheik Ahmad Abdi Godane, aka Abu Zubair.

Africa Oil, and its partners Red Emperor Resources and Range Resources, started drilling in January and are to complete the first oil well in Somalia in more than 20 years in the next few weeks.

The Canadian and Australian operators say the Dharoor field could hold up to 1.2 billion barrels of oil. Other surveys indicate the Puntland region has a potential 10 billion barrels.

If that's correct, it would place Somalia, a former Italian colony that has been torn by clan warfare since dictator Mohammed Said Barre was overthrown in 1991, among the top 20 oil states in the world.

But it's the potential for oil and natural gas off Somalia in the Indian Ocean that's seen as big prize, not just for Puntland but for the rest of Somalia as well.

The entire East African coastline further south, all the way to the former Portuguese colony of Mozambique, is seething with exploration by international oil companies, on land and offshore, and is expected to rival the massive fields found in West Africa.

Somali officials say the potential yield is comparable to Kuwait, which has proven oil reserves of 102 billion barrels. That could make Somalia one of the richest oil states in the world.

There are likely to major natural gas fields as well. Fields containing reserves estimated at 110 trillion cubic feet of gas have been found off Mozambique and Tanzania in recent months.

U.S. and Chinese companies have expressed interest in the Somali region but so far have shown no sign of moving into the war zone.

Puntland, whose ramshackle economy appears to rest on Somali pirates who prey on shipping in the Indian Ocean, has largely kept out of the violence wracking the country to the south.

But that may be changing if al-Shabaab seeks to muscle in on the anticipated oil boom in a region that's languished well off the beaten the beaten track for years but may not be remote for much longer.

On Feb. 23, British Prime Minister David Cameron pledged at an international conference on Somalia that his government was offering humanitarian aid and security assistance in return for a stake in the country's future energy industry.

That was seen by some as little more than a cynical Western ploy to grab Somalia's oil wealth. The liberal Guardian newspaper of London said Britain was "involved in a secret high-stakes dash for oil in Somalia."

Abdulkadir Abdi Hashi, Puntland's minister for international cooperation who sealed the exploration deal with Africa Oil, said Puntland was interested in having the British oil giant BP as a partner "to help us explore and build our oil capacity."

The problem is that as Somalia's energy prospects brighten, the country could become a battleground for neighboring states like Ethiopia, Uganda and Kenya, which have troops there fighting al-Shabaab.