The death toll in the deadly attack on Nairobi’s Dusit Hotel has risen to 15 as of early Wednesday morning as rescue operations continued around the clock overnight to free workers still trapped inside the hotel. 

The sound of gunfire was once again heard Wednesday morning, according to media reports.

Staff at a Nairobi morgue said the bodies of 11 Kenyans, an American and a Briton had been identified. The identity of the remaining two victims still needs to be determined as they were not carrying their passports on them.

Al Shabaab claimed responsibility for the deadly assault, involving explosions and gunfire, which began on Wednesday afternoon when four militants attacked the hotel in the upscale Westlands area of the Kenyan capital. 

On Monday the trial of Al Shabaab members responsible for the 2013 attack on the Westgate mall, which killed 69 people and injured 175, began in Nairobi.

"Our fighters killed 47 enemies inside the complex. The mujahideen are still in control of most parts of the building complex," Abdiaziz Abu Mus'ab, the group's military operations spokesperson, told Al Jazeera on Tuesday.

The first explosion took place in the parking lot and involved three vehicles before a suicide bomber detonated his explosives in the foyer of the hotel.

Security forces and emergency services quickly arrived on the scene, evacuating around 150 workers from the area and rushing the injured to hospitals where an urgent appeal for blood donations was made. Many of those still trapped in the building appealed for help via their mobile phones while family members prayed for their safety.

In a statement released late Tuesday night Kenyan Interior Minister Fred Matiangi’i said the buildings at the scene of the attack had been secured and dozens of people evacuated.

“The security teams have evacuated scores of Kenyans and other nationalities from the buildings. We are now in the final stages of mopping up the area and securing evidence and documenting the consequences of these unfortunate events,” said Matiangi’i. He also thanked its friends in the international community for the support and collaboration that Kenya has received. 

African Union chief, Moussa Faki, condemned the attack and commended Kenyan security forces for their "swift response". UN Secretary-General Antonio Guterres also denounced "the horrible terrorist act".

Kenya has been battling Al Shabaab militants for a number of years following its military intervention in Somalia in October 2011 to fight the organisation.

The group has since carried out numerous attacks in the East African country targeting both civilians and the military. On April 2, 2015, an Al Shabaab attack killed 148 people at the university in Garissa, in eastern Kenya.