A German of Somali origin is suspected to have been the suicide bomber who struck in Somalia’s capital, Mogadishu, on Sunday, a Somali intelligence officer has told the BBC.
The male bomber was believed to be from the city of Bonn, said the officer, who spoke on condition of anonymity as investigations were continuing.
The attack on the five-star Jazeera Palace Hotel killed 15 people.
Al-Shabab, which is linked to al-Qaeda, said it carried out the bombing.
A number of people from the US and Europe are known to have previously travelled to Somalia to join the group.
US President Barack Obama, who is visiting neighbouring Ethiopia and Kenya, condemned the attack.
Ali Khalif Galayd, former Somali prime minister, told BBC Focus on Africa:
I was present in Westgate [shopping centre in Kenya’s capital, Nairobi when militants attacked on 21 September 2013] in the Art Cafe, and I was staying in this Jazeera hotel… I was about to leave my room before 4pm when all hell broke loose.
Somebody was teasing me saying that I’m like a cat and I have nine lives – I didn’t like that, but I was pleased, thank God, to be alive.
I was standing when the explosion happened and I fell and then about three doors and probably two windows blew into the room.
The door that led to the balcony fell on my chest and my left thigh – I have a few cuts and bruises but, thank God, I’m alive.
Westgate was more troubling because there was shooting everywhere. Here it was a massive explosion, so if you survived that, there was nothing else.
It will probably be part of my emotional baggage to carry round in terms of trauma – but I’m very happy and thank God it was not as destructive in terms of human lives.
The BBC Mohamed Moalimu in Mogadishu says that foreign experts are at the site of the blast to help with investigations.
The Somali intelligence officer also at the site told him the bomber was a Somali-German.
Germany has not yet commented on the allegation.
The officer said they were still trying to establish how the bombing was masterminded, our reporter says.
A lorry was used to carry out the attack on the hotel near the heavily secured airport – and the blast was one of the largest to have hit the city in about eight years, he says.
It is the third time the Jazeera Palace Hotel, which was opened by a Somali who returned from the US, has been the target of al-Shabab militants.
It is popular with international diplomats and also accommodates several embassies including those of China, Qatar and Egypt.
A Chinese embassy worker was among the dead as well as three members of the hotel staff, our reporter says.
Who controls Somalia?
Al-Shabab is battling Somalia’s government for control of the country. While security in Somalia has improved, the group still attacks Mogadishu regularly.
On Saturday, a member of the Somali parliament and an official from the prime minister’s office were killed in separate attacks in the capital claimed by al-Shabab.
The militants have also targeted neighbouring countries, killing almost 150 people in an assault on Garissa University College in Kenya in April.
In 2013, four of its fighters killed 67 people in an attack on the upmarket Westgate shopping centre in Kenya’s capital, Nairobi.