Kenya's capital, Nairobi, is on alert after several lions escaped from a nearby national park overnight and strayed into the city.

One lioness and her two cubs have been recaptured, and two other animals are believed to have gone back into the Nairobi National Park on their own accord.

But it is not clear whether more lions remain on the loose.

Residents have been told to report any sightings to a free telephone line.

"Lions are dangerous wild animals. Don't confront them when you encounter them," Paul Udoto, spokesman for the Kenya Wildlife Service (KWS) tweeted.

The park is separated by a main road from densely populated neighbourhoods, including Kibera slum, in the south of the city.

The BBC's Emmanuel Igunza in Nairobi says some residents of Kibera, one of the largest slums in Africa, are angry that the KWS is taking so long to hunt down the lions.

Two of the lions were spotted not far from the slum earlier in the morning.

There has been confusion about how many lions escaped and wildlife officials are currently verifying numbers inside the park, our reporter says.

It is estimated about 30 lions live there in an area spread over 17 sq km (45 sq miles).

'Keep children locked up'

KWS senior warden Nelly Palmeris said three lions were found in a housing complex at a military barracks near the park.

They had not wandered too far as the lioness was still nursing her two cubs, she said.

This KWS vehicle is stationed near Kibera where two lions were sighted early in the morning

KWS senior warden Nelly Palmeris assured residents all was being done to find the lions

Mr Udoto said he was concerned that people would try to tackle the lions themselves, as has happened in the past.

In 2012, four cubs had to be placed in an orphanage after a similar incident led to their mother being killed.

Answering a question on Twitter from a worried mother, Mr Udoto advised her to keep her children locked inside until the lions had been safely returned to the park, adding such incidents were the "perils of born town lions".

Nairobi National Park is fenced in on the city side but is open elsewhere to allow for the annual wildlife migration.

Conservationists say a loss of habitat for lions in Kenya means they are increasingly coming into conflict with humans, putting their survival at risk.