Explosions and gunfire heard in Kenyan capital Nairobi - Aljazeera.com

Two explosions and gunfire were heard at an upscale hotel complex in Kenya's capital on Tuesday afternoon, according to witnesses and police.

The attack on the Dusit hotel complex - which also houses offices and banks - sent people fleeing for their lives, with black smoke rising from the scene.

"We are under attack," a person in an office inside the complex told the Reuters news agency.

"It is terrible. What I have seen is terrible. I have seen a human as I ran out and there is what looks like minced meat all over," said one a man who said he ran from the scene. He did not give details.

Gunfire continued several minutes after the first reports. A bomb disposal unit was on the scene and vehicles were being cordoned off for fear that they contained explosives.

"We have sent officers to the scene, including from the anti-terrorism unit, but so far we have no more information," Charles Owino, the police spokesman, told AP news agency.

Shabab claim responsibility

Somalia-based armed group al-Shabab claimed responsibility for the attack that came a day after trial began in deadly Westgate mall attack case that left 67 people dead. The group said the attack was ongoing.

Cars are seen on fire at the scene of the attack [Thomas Mukoya/Reuters]

"We are currently conducting an operation in Nairobi," the group's military operations spokesman told Al Jazeera.

Kenyan prosecutors say the four suspects in the Westgate case currently on trial committed a terrorist act and used false documents. The men deny all charges.

The east African country faced a spate of attacks after it sent its army into Somalia in 2011 to fight the al-Qaeda-linked group.

Tuesday's attack comes exactly three years after the armed group overran a Kenyan army base in Somalia, killing dozens of soldiers.

On April 2, 2015, in one of the most gruesome attacks on Kenyan soil, al-Shabab killed 148 people, most of them students, at a university in Garissa, eastern Kenya.