A foreign female tourist has been shot dead in Kenya's port city of Mombasa, police have told news agency AFP.

A Twitter user posted the unverified picture showing a woman covering the body of the victim, whose identity has not yet been disclosed.

Another Twitter user said the woman is German. However, this has not yet been confirmed.

"We are pursuing the killers who have shot the tourist," Mombasa police chief Robert Kitur said. "We are yet to establish if there is anything stolen from her."

The shooting took place close to where a female Russian tourist was killed on 6 July by unknown gunmen.

The US Peace Corps is suspending its programs in Kenya because of security concerns and is pulling more than 50 volunteers out of the country until threat levels decrease, the Peace Corps and State Department said Thursday.

The evacuation comes a few days after gunmen suspected of belonging to terror group al-Shabab killed four people and injured several others in Mombasa.

The militants issued a statement last month warning foreign tourists to stay out of Kenya.

"Kenya is now officially a war zone and as such any tourists visiting the country do so at their own peril."

Following the statement, the UK's Foreign and Commonwealth Office (FCO) advised tourists to avoid coastal and low-income areas.