Nairobi - Kenya's interior minister and police chief were removed from their posts on Tuesday, hours after Somalia's Shabaab rebels carried out a fresh massacre in the northeast of the country.
In a televised address to the nation, President Uhuru Kenyatta also vowed his security forces will "intensify the war on terrorism" after a spate of killings in the country by the al-Qaeda-affiliated insurgents.
A group of Shabaab rebels stormed into a quarry near the border town of Mandera shortly after midnight, and police and officials said they weeded out 36 non-Muslims for execution.
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Those labourers not shot as they slept were placed in lines in the dusty quarry, with insurgents shooting most in the head but also beheading others.
Their bodies were flown to Nairobi later on Monday on a military transport plane.
The Shabaab said in a statement their latest cross-border attack was fresh retaliation for Kenya's 2011 invasion and continued presence in Somalia, as well as its treatment of Muslims in the troubled port city of Mombasa.
The assault came just over a week after the Shabaab executed 28 people grabbed from a bus travelling from Mandera, on the frontier between Kenya, Somalia and Ethiopia.
Kenyatta, however, said Kenyan troops would stay put in Somalia, where they are now part of an African Union force battling the Shabaab and supporting the war-torn country's internationally-backed government.
"This is a war and a war that we must win, we must win it together," he said. "The ultimate aim of this atrocious campaign is to create an extremist caliphate."
He called the Shebab "deranged animals" who had killed more than 800 people in attacks inside Kenya, including 500 civilians and 300 security officers.
"We will not flinch or relent in the war against terrorism in our country and our region. We shall continue to inflict painful casualties on these terrorists until we secure our country and region."
The Kenyan government has been under fire since last year's Shabaab attack on the Westgate shopping mall in Nairobi, in which at least 67 people were killed in a siege involving just four gunmen and which lasted four days.
Dwindling public confidence
Sending condolences to the families of the latest victims, the United States said there was "no excuse or justification for this kind of terrorist violence."
Washington had been "very clear about the threat posed" by Shabaab, said State Department spokeswoman Marie Harf, adding US officials "vigorously condemn" the group's "continued cowardly, brutal targeting of civilians".
Worries over internal security mounted when Shabaab rebels massacred 100 people in a string of raids against villages in the Lamu region on the Kenyan coast in June and July.
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The sacked interior minister, Joseph Ole Lenku, has been ridiculed for his statements on the security situation, while national police chief David Kimaiyo has been accused of repeated lapses -contributing to dwindling public confidence in the security apparatus.
According to Kenyan media, intelligence officials had alerted police to the presence of Shabaab fighters in the northeast before last month's bus attack, but police had failed to react.
Kenyatta announced Ole Lenku had been replaced, and that Kimaiyo has been allowed to retire early. Joseph Nkaissery was nominated to take over as interior minister.
Labourers in the largely Muslim and ethnic Somali north-eastern regions often come from Kenya's central highlands, where Christians make up about 80% of the population.
Shabaab vow more attacks
The Shebab meanwhile boasted of having killed "nearly 40 Kenyan crusaders" in the quarry, and signalled more killings were being planned.
"This latest attack was part of a series of attacks planned and executed by the mujahedeen as a response to Kenya's occupation of Muslim lands and their ongoing atrocities," Shebab spokesperson Sheikh Ali Mohamud Rage said in a statement to AFP.
He threatened more attacks on Kenyan soil by their "Saleh Nabhan brigade" - named after slain Shebab commander and Kenyan citizen Saleh Ali Nabhan, killed in 2009 by US special forces for his role as al-Qaeda's chief in east Africa.
"We are uncompromising in our beliefs, relentless in our pursuit, ruthless against the disbelievers and we will do whatever necessary to defend our Muslim brethren suffering from Kenya's aggression."