Deadly riots broke out in Kenya's main port of Mombasa on Monday after the assassination of a radical cleric linked to Somalia's al-Qaida-allied Shebab militants.

At least one person was hacked to death as thousands of angry protestors took to the streets after Aboud Rogo Mohammed -- who was on U.S. and U.N. sanction lists for allegedly supporting the Shebab -- was shot dead.

Two German tourists and two pilots were killed when their airplane crashed Wednesday in Kenya's renowned Maasai Mara national park, with at least three other tourists badly injured, police said.

"Four people died on the spot, while three others were seriously wounded," said local police chief Peterson Maelo. "Those injured have been taken to Nairobi for treatment."

At least 48 Kenyans were hacked or burnt to death in ethnic clashes between two rival groups, the worst single attack since deadly post-election violence four years ago, police said Wednesday.

"It is a very bad incident.... They include 31 women, 11 children and six men," regional deputy police chief Joseph Kitur said of the attack, which took place late Tuesday between the Pokomo and Orma peoples in the rural Tana River district.

Kenya's High Court on Thursday quashed bail for two Iranians on trial for possessing explosives allegedly for use in bomb attacks in Kenya.

Ahmed Mohammed and Sayed Mansour, who were arrested in June and charged with suspected links to a terror network planning bombings in Mombasa and Nairobi, are accused of possessing 15 kilos (33 pounds) of the powerful explosive RDX.

At least five Ugandan servicemen survived the crash of two army helicopters in Kenya en route to war-torn Somalia with two confirmed dead, officials said Tuesday.

"The good news is that we have managed to find five survivors and they have just been airlifted to safety," said Simon Gitau, a senior warden with the Kenya Wildlife Service, which is involved in the rescue operation.

Emergency teams on Monday searched for two Ugandan army helicopters feared to have crashed in thick forest in Kenya while flying to Somalia to support forces fighting insurgents there, officials said.

Seven Ugandan servicemen aboard a third helicopter which was part of the same mission were rescued, Kenyan army spokesman Bogita Ongeri said.

Six people were wounded Wednesday when an explosive device went off at the Dadaab refugee camp in northeastern Kenya, the Kenyan Red Cross said.

The device, believed to be a hidden bomb, exploded as non-food items from an aid agency were handed out in Dadaab, the world's largest refugee camp, which houses over 465,000 refugees, mainly Somalis fleeing drought and conflict.

A grenade attack wounded four people in Kenya's Wajir border region with war-torn Somalia, police said Thursday, the latest in string of attacks in the volatile region.

Attackers in Wajir, some 100 kilometers from Somalia, hurled grenades into a restaurant and a shop late on Wednesday, said regional police chief Philip Tuimur.

Two Iranians charged with possession of explosives reportedly to be used in bomb attacks in Kenya were released on bail Monday, but ordered to surrender their passports by a Nairobi court.

Ahmed Mohammed and Sayed Mansour, who deny all charges, were arrested last month in the port city of Mombasa, reportedly with 15 kilos (33 pounds) of powerful explosives.

Aid agencies warned Thursday that a critical shortage of funds was threatening lives in Kenya's Dadaab refugee camp complex, the world's largest, risking worsening an already volatile security situation.

"Tens of thousands of lives (are) at risk with money for vital services set to run out in two to three months," said the group of eight aid agencies, including CARE, International Rescue Committee, Oxfam and Save the Children.