The Kenyan capital's main international airport was shut for several hours on Sunday following the crash-landing of a domestic flight, airport officials said.

The Kenyan Airports Authority said a Fokker 50 flying from Wajir in the northeast and operated by Skyward suffered landing gear failure and landed on its belly at Jomo Kenyatta International Airport, blocking the sole runway. No casualties were reported.

Six people died and 11 were injured in a central Nairobi building collapse, with fears that the toll could rise as crews continued to dig through the rubble, officials said Thursday.

The four-floor building came down early Wednesday. At least 10 survivors emerged from the debris the same day, but it remained unclear how many people could still be trapped.

It is an image famous in a thousand postcards: giraffe, rhino and zebra pacing the savannah with city skyscrapers towering in the background.

But flanked by one of the continents fastest growing cities, Kenya's capital Nairobi, east Africa's oldest national park is under threat.

President Uhuru Kenyatta arrived in Nairobi Thursday to crowds cheering him home, a day after becoming the first sitting president to appear before the International Criminal Court on crimes against humanity charges.

Kenyatta, who was given a red carpet welcome with a military honor guard as well as dancers singing songs declaring he "is innocent," had appeared in The Hague-based court on Wednesday.

Kenya began emotional commemorations on Tuesday to mark the first anniversary of Nairobi's Westgate mall massacre, remembering the 67 people killed by Somali Islamist gunmen and those who risked their lives to stop them.

In a speech at a memorial site opened at the capital's National Museum, First Lady Margaret Kenyatta said the east African nation had been "seriously scarred" but not broken by the attackers from the Al-Qaida-affiliated Shebab rebels.

Kenyan police on Wednesday produced a small arsenal of weapons recovered after last year's Westgate mall massacre, in the ongoing trial of four men accused of helping the gunmen.

The slow moving trial in Nairobi -- which opened in January -- has heard evidence from people who were at the mall when the gunmen from Somalia's al-Qaida-linked Shebab launched their attack in September 2013, killing at least 67 people.

At least four people died when a cargo plane crashed into a building shortly after takeoff Wednesday from the Kenyan capital's main airport, the busiest in east Africa, aviation authorities said.

"A Fokker 50 cargo plane with four people on board has this morning crashed at a commercial building," after taking off from Nairobi's Jomo Kenyatta International Airport (JKIA), Kenya Airports authority said in a statement.

At least two people were killed and dozens more wounded when bombs exploded in two buses on a busy highway in the Kenyan capital Nairobi, officials said.

The bombings came just a day after twin attacks in the restive port city of Mombasa, including a grenade attack on a bus, which killed four, and a bombing outside a luxury beach hotel.

A blast in Eastleigh, the main Somali district of the Kenyan capital Nairobi, killed at least five people Monday, an official at the national disaster operations center said.

"Police are securing the area for emergency response services," the official said. Eastleigh has in recent years been the scene of several explosions usually attributed by the police to Islamist extremists.

Islamist gunmen who shot dead scores of people in a Nairobi shopping mall last year were in apparent disagreement over whether they should kill women and small children, a court in Kenya heard on Thursday.

Witness Geoffrey Kotia, who was supervising children's activities in the upmarket shopping center, said he was shot by the attackers, accused of killing Somalis and mockingly told to telephone Kenyan President Uhuru Kenyatta for help.