The United States secured a 10-year lease for a military base in Djibouti that it uses to launch counterterrorism missions, including drone strikes, in Yemen and the Horn of Africa.
US President Barack Obama and his Djiboutian counterpart, Ismail Omar Guelleh, announced the renewed lease on Camp Lemonnier as they met at the White House on Monday, vowing to counter al-Qaeda and al-Shabab militants in the region.
The new deal represents a major increase in rent, as Washington reportedly pays US$38 million a year under the current lease.
"Camp Lemonnier is extraordinarily important to our work throughout the Horn of Africa but also throughout the region. We very much appreciate the hospitality that Djiboutians provide," Obama said.
"Overall, this is a critical facility that we maintain in Djibouti, we could not do it without the president's co-operation, we're grateful for him agreeing for a long-term presence there." he added.
Guelleh said his East African country and the US were linked in a "strategic partnership" to deal with "the fight against terrorism, piracy and human trafficking in our region".
The US military uses Lemonnier as a base for around 4,000 US and allied personnel, as a staging area for assaults on suspected al-Qaeda militants in Yemen and al-Shabab forces in Somalia.
In a joint statement after the two presidents met, Obama promised more US assistance and equipment for Djibouti's forces, including for troops deploying to the African Union mission in Somalia.
Obama also pledged more development aid for Djibouti's economy, including help improving the country's electricity network.
After the terrorist attacks on the US on September 11, 2001, the US presence has steadily increased at the Djibouti base, serving as a hub for special-operation forces and a growing fleet of armed and unarmed drones as well as other aircraft.
US officials, anxious to maintain a low profile for the American military in Africa, tend to divulge few details about operations at the base.
It is the biggest in a network of airfields in East Africa, including runways in Uganda and Ethiopia, that the US uses to counter al-Qaeda-linked militants in Somalia, Yemen and elsewhere.
Washington recently agreed to move its drone base in Djibouti from Lemonnier, which is near the country's international airport, to a more remote location, following concerns over possible collisions between the unmanned planes and commercial aircraft.
The base, originally created by the French Foreign Legion, was initially seen as a temporary outpost after the September 11 attacks, but the US military has drafted long-term plans to keep operating out of Lemonnier.
The Pentagon reportedly has informed the US Congress of plans for a dramatic expansion of its facilities in Djibouti, proposing more than a billion dollars in construction projects.