Somalia's al-Qaida-linked al-Shabaab insurgents are planning further attacks in the Horn of Africa nation of Djibouti, the Foreign Office has warned, after suicide bombers attacked a crowded restaurant last month.

"There are credible reports that al-Shabaab plan, and have the capability, to attack targets in Djibouti, including western interests," the Foreign Office said, noting that "there is a high threat from terrorism" in the port city.

Troops from Djibouti are part of the African Union in Somalia fighting the militants, and Djibouti's port also serves as a key base for ships taking part in international anti-piracy operations off the Somali coast.

"Djibouti and western interests within Djibouti may be seen as a legitimate target by al-Shabaab because of its support to the Somali government and its participation in the African Union peacekeeping mission," the Foreign Office statement said.

Last month at least one person was killed and several wounded when two suicide bombers blew themselves up in a restaurant, the first attack in Djibouti to be claimed by al-Shabaab since it joined the AU force in 2011.

Al-Shabaab said the attack was also carried out in retaliation to Djibouti's hosting of the United States' biggest military base in Africa.

The US base is used for operations across the region, including drone strikes against Islamists in Somalia.

France, the former colonial power, also has a base in the country.

The UK government has also released warnings to citizens in several east African nations – including Ethiopia, Djibouti, Kenya and Uganda, who all have troops in Somalia – speaking of the threat of attacks at public screenings of the World Cup.

"Previous terrorist attacks in the region have targeted places where football matches are being viewed," the government said, adding that crowded areas including transport hubs, hotels, restaurants and bars are also possible targets.

During the World Cup final four years ago Somali Islamist insurgents killed at least 76 people after setting off explosions that ripped through two restaurants in the Ugandan capital Kampala.