Nairobi, Sep 21 (IANS): At least 20 people were killed and 50 wounded when gunmen opened fire in a shopping mall in the Kenyan capital of Nairobi, according to the Kenyan Red Cross.

Shoppers were still being held hostage on the third floor of the building while police have taken control of the first and second floors, Xinhua reported citing witnesses.

Authorities were yet to confirm the actual number of casualties.

The standoff was still continuing hours after the shootout between police officers and a group of armed men at the Westgate shopping mall which is visited mostly by foreigners and the rich in this East African country.

Earlier, Inspector General of Police David Kimaiyo, in an initial report said five people were wounded in the exchange of fire. He called for calm and assured of the capability of dealing with the situation.

Kimaiyo said the shopping mall had been cordoned off by the police and announced that he "will issue a comprehensive statement later".

"We urge the public to remain calm, stop any form of speculation, especially online and let us resolve this quickly," Kimaiyo said.

"Gunshots still can be heard from inside the mall. The police have taken charge of the ground floor. The public should stay away from Westgate and its environs and we ask the media to refrain from any unnecessary comments," Kimaiyo added.

Mutea Iringo, principal secretary in Kenya's interior ministry, confirmed that the hooded men were indeed armed criminals but have not established their identities.

Iringo said the government has dispatched air surveillance.

The East African country has been grappling with insecurity since October 2011 when the Kenya Defence Forces launched a cross-border incursion into southern Somalia in pursuit of Al-Shabaab militants who had kidnapped several foreigners on the Kenyan side along the border, posing a serious threat to the country's pillar industry of tourism.