Attacks prompt sacking in Kenya

Survivors said gunmen crept into a workers' camp overnight and carried out executions, similar to the targeting of bus passengers 10 days ago in Mandera County. The area lies close to Kenya's border with Somalia.

In a televised address, President Kenyatta said he had removed interior minister Joseph Ole Lenku and accepted police chief David Kimaiyo's request to retire.

Both had been criticized for failing to stop an attack series that included last year's al Shabab attack on Nairobi's upscale Westgate mall, where 67 people were killed.

The rebels also massacred 100 people in the Lamu region on the Kenyan coast in June and July.

Intensify crackdown, says Kenyatta

Kenyatta named former army general Joseph Nkaisery as replacement minister and said the government would "intensify" its "war on terrorism," and would stop al Shabab from creating an "extremist caliphate" in the region.

"This is a war and a war that we must win, we must win it together," he said

The president himself has faced public criticism over reports that he attended a Formula 1 motor race during a state visit to the United Arab Emirates just after the bus attack on October 22.

Rebels cite Kenyan presence in Somalia

Responsibility for the quarry attack was claimed by al Shabab spokesman Sheikh Ali Mohamud Rage.

He cited alleged atrocities by Kenyan troops stationed since 2011 in Somalia whose UN-backed government is backed by an African Union force.

Labourers in the largely Muslim and ethnic Somali northeastern regions often come from Kenya's central highlands, where Christians make up about 80 percent of the population.

Divisions feared

Mandera County Senator Billow Kerrow said al Shabab was trying to "create divisions" between local Muslims and Christians.

Kerrow said the rebels were facing "no resistance," despite central government assurances that the presence of police and the army would be boosted.

Kenyatta's chief of staff, Joseph Kinyua, on Tuesday tried to persuade non-Muslims from leaving Mandera. Last week, about 100 sheltered at an army base, demanding that the government evacuate them.

In Somalia earlier this year, al Shabab was driven out of several strongholds north and south of the capital Mogadishu by Somali and African Union troops.

In Nairobi, analyst Cedric Barnes of the International Crisis Group said the attacks at the quarry and on the bus were "partly the result of al Shabab being squeezed [out] of Somalia.

ipj/jr (AFP, Reuters, AP)