Minibus driver Solomon Murimia calls on clients next to his "matatu" minibus with a painting depicting US Presidents Abraham Lincoln and Barack Obama and US civil rights leader Martin Luther King on July 22, 2015 in Nairobi
Nairobi (AFP) - Presidential tours are always expensive, but especially so when the country being visited is, like Kenya, the scene of regular terrorist attacks.
US and Kenyan officials are fixated on making sure Al-Qaeda's Somali-led affiliate, the Shebab, cannot violently disrupt the US presidential visit this week.
"The American president is a high value target so an attack, or even an attempt, would raise the profile of Shebab," warned Richard Tutah, a Nairobi-based security and terrorism expert.
Mitigating that is an overwhelming security presence in the capital. "The level of security is suffocating," said Abdullahi Halakhe, a regional security analyst.
President Barack Obama is due to address an international business summit in Nairobi, an event the US embassy itself warned could be "a target for terrorists".
The closely-held details of the security arrangements for the three-day visit are a source of endless fascination and speculation in the Kenyan media.
"US President Obama's Security Gadgets Arrive," read the headline in The Star, a tabloid with a talent for Kenyan security scoops.
"A US military cargo plane... will ferry in a whole range of secure advanced communications equipment, some of it to be used by President Obama himself when he lands," the paper breathlessly reported.
Hundreds of American security personnel have arrived in Kenya in recent weeks. Kenyan media reports that three hotels -- the Sankara, Villa Rosa Kempinski and Intercontinental -- have been scouted by the Secret Service.
- The Beast -
This week the distinctive Osprey tilt-rotor aircrafts, usually stationed at the US military base in Djibouti, flew over Nairobi alongside a White Hawk chopper with presidential insignia, causing much excitement on social media.
Other military helicopters have been flown in reportedly from a US Special Forces facility at Kenya's Manda Bay base, which serves as a launchpad for raids on Shebab in Somalia.
Kenya is also playing its part. Nairobi's police commander Benson Kibue said on Wednesday that 10,000 police officers -- roughly one quarter of the entire national force -- would be deployed to the capital.
Kibue also said that a series of main roads would be closed on Friday and Saturday, in a move that will paralyse the traffic-clogged city.
The Kenya Civil Aviation Authority announced that national airspace will be closed for 50-minutes on arrival and 40-minutes on departure, unwittingly publicising the exact dates and timings of Obama's travel.
Kenya and Islamic extremism have been entwined since 1998 when Al-Qaeda bombed the US embassy in Nairobi.
While in capital, Obama is expected to travel in his bespoke, bomb-proof limousine, nicknamed 'The Beast'.
The $1.5 million car is a moving fortress with eight-inch thick steel plates, five-inch thick bulletproof glass, Kevlar-reinforced tyres, and a presidential blood bank in the boot.
The Beast is one of as many as 60 vehicles flown into Kenya for the visit, Kenya Airports Authority officials told The Standard newspaper, as snapped photos of the vehicles arriving on cargo planes were shared on social media.
- Fight against terror -
Obama's three-nation tour of Africa in 2013 was estimated to have cost between $60-100 million.
A planning memo leaked to the Washington Post revealed that security measures for the visit to Senegal, South Africa and Tanzania included a navy aircraft carrier moored offshore, fighter jets providing 24-hour air cover, more than a dozen armoured limousines flown in and sheets of bulletproof glass imported to protect the hotels where he stayed.
Bill Clinton's 1998 six-nation Africa tour cost $42.8 million -- not including Secret Service expenses which were classified -- according to the US Government Accountability Office.
Three-quarters of those costs were incurred by the Department of Defence which flew 98 airlift missions taking equipment to Africa for the tour.
No US president has ever visited Kenya which, along with its neighbour Ethiopia -- also due a presidential visit on this tour -- is a crucial ally in fighting Islamic extremism emanating from Somalia.
The Shebab has proved itself adept at launching low-tech assaults on soft targets such as Nairobi's Westgate mall in 2013, Garissa's university in April and small towns on Kenya's coast, but it has failed to emulate the terrorist spectacular of 1998.
Obama is expected to visit the Nairobi bomb site during the Kenya leg of his trip.
In a televised address on Wednesday, ahead of Obama's visit, Kenya's President Uhuru Kenyatta acknowledged the threat posed by terrorists.
"Our country has endured the attacks of depraved, ideological criminals," he said. "We have fought them unrelentingly, and they know, as well as we do, that they will lose."
Kenyatta added that there is "very close cooperation" with the United States and "the fight against terror will be central" to his scheduled meeting with Obama.
In a press conference in Washington this month Obama bemoaned the heavy security restrictions during his visit to Kenya, his father's homeland.
"I will be honest with you, visiting Kenya as a private citizen is probably more meaningful to me than visiting as president, because I can actually get outside of the hotel room or a conference centre," Obama said.