As the global hunt continues for Osama bin Laden and other al-Qaida terrorist suspects, the small, Muslim country of Djibouti, in the Horn of Africa, has been emerging as a key strategic ally for the United States.

It has been a brutal week for the 15,000 U.S. soldiers of the 24th Marine Expeditionary Unit, training at a remote corner of Djibouti. The Marines have been conducting live-fire exercises that simulate real desert warfare.

Today, they are practicing advancing on enemy positions, supported by artillery units.

The exercise is not easy, and the intense heat of the Djiboutian desert is taking a toll on the soldiers, who are carrying up to 40 kilograms of equipment.

But a spokesman for the expeditionary unit, Captain Dan McSweeney, says the Marines consider Djibouti's harsh climate and desolate terrain the perfect environment to prepare for possible conflicts against terrorists in the region.

"They are acclimating themselves to the environment. Now that we are working in CENTCOM, it is very important to get to know this climate and region, and that's what we are doing."

CENTCOM is the United States Central Command, which has been directing the U.S.-led war against al-Qaida and the Taleban in Afghanistan. It is now preparing to set up a new regional military headquarters in Djibouti to oversee operations aimed at tracking down al-Qaida leaders and their operatives who remain at large.

The U.S. military chose Djibouti primarily because of its strategic location. It lies just across the Red Sea and the Bab al-Mandab Strait from Yemen, the ancestral home of al-Qaida leader Osama bin Laden, and a suspected breeding ground for many of his followers.

Western intelligence officials say they believe many al-Qaida operatives are trying to find refuge, and to recruit new members in the vast, lawless areas of Yemen, Somalia and elsewhere in Africa. Earlier this month, an unmanned aircraft, reportedly operated by the U.S. Central Intelligence Agency, fired a missile at a car in the desert in Yemen, killing six al-Qaida members, including a top bin Laden associate.

Djibouti is also next door to another potential terrorist haven, Somalia. U.S. officials are concerned that Al Ittiyad al Ismalia, a militant Islamic group with links to al-Qaida operating out of southern Somalia, could emerge as a serious threat to the United States.

To deny al-Qaida and other potential terrorists access to waterways and shipping lanes around the Horn of Africa and the nearby Gulf of Aden, Western countries, including Germany and Spain, have been conducting large-scale maritime patrol missions for several months, using Djibouti and its deep-water port as a logistical base.

In the capital, Djibouti City, the U.S. military presence can be better heard than seen. Helicopters fly patrols over a new U.S. military base at Camp Le Monier, a former French barracks near the international airport. At least 800 troops, including Special Operations forces, are stationed here amid tight security. But the camp could grow significantly larger, if the new joint task force headquarters, with 400 additional Marines, is based here sometime early next year.

Asked why Djibouti, a Muslim nation with cultural and historical ties to both Somalia and Yemen, has allied itself with the United States and the West in the war against terrorism, Prime Minister Dileita Mohamed Dileita says the country recognizes the danger al-Qaida poses, not only to Western nations, but to all countries in the world.

Mr. Dileita said Djibouti rejects any connection between Islam and terrorism. He said, just like many other Arab nations who are cooperating with the West, Djibouti believes the fight against terrorism is about the fight for peace and stability, not about religion.

This is not the first time the United States and European countries have used Djibouti as a military hub. In the early 1990s, the United States used Djibouti to refuel its planes during the Gulf War. France has maintained a significant military and technical presence in the country since Djibouti gained its independence from France in 1977. Years later, France still has a presence, with about 10,000 soldiers, nationals, and diplomats in the country.

Djiboutian officials say they are hoping their cooperation in the war against terror will translate into more economic assistance from the United States and countries in Europe. With a population of 600,000 people, Djibouti has almost no resources, and remains one of the poorest countries in Africa.

But Prime Minister Dileita says cooperation does not mean the country is now being used as a base for specific U.S. actions against terrorists. He vehemently denies recent media reports that claim the Central Intelligence Agency used an airfield in Djibouti to launch the unmanned aircraft that targeted the al-Qaida operatives in Yemen.

"It's not true, it's not true," Mr. Dileita said. "If Americans wanted to fight al-Qaida in Yemen, they would launch attacks from inside Yemen itself, because American troops are there as well."

The U.S. Marines training in the desert say they do not know how long they will be welcome in Djibouti. Although the people of Djibouti are used to French troops on their soil, they may not be so willing to accept a long-term American troop presence, especially if the United States is seen conducting unpopular or controversial military campaigns in the region.

But Western diplomats say, for now, the Djibouti government appears to believe that the benefits of an alliance with the United States will outweigh the potential problems such an alliance may cause at home.