Attacks leave 13 dead as Kenya marks 50th anniversary of independence
Agence France-Presse in Nairobi
Thirteen people have been killed in four attacks in Kenya - one of which targeted tourists - during week-long celebrations to mark the country's 50th anniversary of independence.
The most recent attack was an explosion on a Nairobi bus that killed four on Saturday.
No group has so far claimed responsibility and there have been no arrests.
Kenya has been the target of sustained attacks since the army sent troops into neighbouring Somalia to fight the country's al-Qaeda-linked al-Shabab insurgents in October 2011.
Eastern Kenya, along the 700-kilometre border with Somalia, has been particularly hard-hit.
Experts are reluctant to draw any link between the armed conflict with al-Shabab and the latest series of attacks. One Western observer said there was "no evidence" yet to link the attacks.
Late on Friday, one person died and three were injured in a double explosion at a market in the town of Wajir, about 100 kilometres from the Somali border.
On Tuesday, eight people were killed, including five police officers, in the Garissa region about 20 kilometres from the Somalian frontier after their vehicle was ambushed. Another policeman is still missing.
Saturday's bus attack blew the vehicle apart, sending shrapnel flying through the air. As well as the four dead, 36 were wounded.
There was also a rare attack on tourists during the week in the tourist location of Mombasa, a predominantly Muslim city.
A grenade thrown at a minibus transporting British tourists hit a window, but did not explode. It was the first attack on tourists since 2011. The British tourists were en route to the famous Masai Mara safari park.
In September 2011, British tourist David Tebbutt was killed as he fought kidnappers in a luxury tourist village on the Kenyan coast, not far from Somalia.
His wife, Judith, was captured and taken to Somalia, where she was freed after six months. The same year, a Frenchwoman living in Kenya, Marie Dedieu, was kidnapped by Somali gunmen from her beachfront home in Lamu, in the south-east of the country, and subsequently died.
"Mombasa has been targeted, but it is true that this attack against tourists is a novelty," the Western observer noted.
He said it was "very different" from the recent Westgate shopping mall terror attack, which left 72 dead.
Many attacks remain unclaimed and the finger of suspicion is often pointed at jihadists.
But there are sometimes serious conflicts between tribes caused by issues such as access to water or grazing land, which can be fuelled by local politicians.
These conflicts, especially in areas where there is deadly weaponry, regularly escalate.