By Ishbel Matheson BBC, Djibouti

A United States general has said the US's mission in the Horn of Africa is to detect and defeat terrorists.

We must keep the terrorist off balance by taking away their perceived safe havens General John Sattler

Speaking in Djibouti, General John Sattler, who is in charge of the Horn of Africa US mission, said his job was to ensure there was no safe haven for terrorists in the Horn of Africa.

Hundreds of elite US soldiers have set up a new base in Djibouti over the past few months.

The US's involvement in this turbulent region has been stepped up since the 11 September attacks in New York and Washington.

'Disrupt and defeat'

Camp Lemonier, as it is called, is heavily guarded, circled with barbed wire, and only a few miles from the border of war-torn Somalia.

Armed soldiers patrol in the blistering desert heat.

The US suspects Yemen, Sudan and Somalia have links to al-Qaeda

Operational headquarters are offshore, with 400 personnel now operational on the American warship, the USS Mount Whitney.

The general in charge, John Sattler, says the mission is to "detect, disrupt, defeat and deny".

"We must keep the terrorists off balance by taking away their perceived safe havens, taking away their external assistance and the material support," he said.

'Long haul'

The vulnerability of the entire region was highlighted by the recent al-Qaeda attacks in Mombasa on the east coast of Kenya.

General Sattler indicated that the US presence in the Horn of Africa was aimed at preventing a repeat of this kind of atrocity.

He said the mission would last as long as Operation Enduring Freedom - the codename for the US-led campaign against terror.

At Camp Lemonier trenches are being constructed.

The Americans, it seems, are digging in for the long haul.