The incident overnight Monday to Tuesday took place some 15 kilometres (10 miles) from the remote town of Mandera and close to the dangerous border with war-torn Somalia, where the al-Qaida-affiliated Shebab and other militia have carried out a string of raids.
The quarry killings follow a separate attack Monday night in the town of Wajir, which left one person dead and 12 wounded when gunmen hurled grenades and sprayed a bar with bullets.
“Our team is on the ground undertaking assessments of the attack,” the Kenya Red Cross said on Tuesday.
The attack in Mandera is close to where Islamists last month executed 28 non-Muslims who were grabbed from a bus.
The Shehab said the bus attack was carried out in revenge for police raids on mosques in Kenya’s key port of Mombasa.
Kenya has suffered a series of attacks since invading Somalia in 2011 to attack the Shebab. Kenyan forces have since joined an African Union force battling the Islamists.
No one has so far claimed responsibility for either of the attacks Monday night.
Several key unions including for civil servants have warned members to leave the restive northeast until the government can ensure their safety.
Professionals working in the largely Muslim and ethnic Somali northeastern regions often come from further south in Kenya, where Christians make up about 80 percent of the population.
On Sunday, Kenyan media reported that the embattled interior minister and police chief may soon be sacked over “repeated lapses” in security following a wave of attacks.
Both officials mentioned in the report have been under fire since last year’s attack by the Shebab against 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.
Worries over internal security mounted when Shebab rebels massacred 100 people in a string of raids against villages in the Lamu region on the Kenyan coast in June and July.