One man was beheaded and five others shot or burned to death in the attack in a village in Lamu County approximately 420 kilometres (260 miles) southeast of Nairobi, police said.
Lamu County Commissioner Irungu Macharia said the attackers were suspected jihadists from Al-Shabaab, the Al-Qaeda-linked jihadist group based across the border in Somalia.
“Our security forces are pursuing them, and we urge support from locals to help us because when we work together we succeed,” he told AFP.
Police said the attackers stabbed and beheaded a local elder and razed his home, and shot dead another man whose body was found on a roadside nearby.
The corpses of four other men burned beyond recognition were found with their hands bound in another location, according to the police report seen by AFP.
“Also several houses were torched within the locality and property of unknown value burnt,” the report said.
Bullet cases were recovered and an investigation is ongoing.
The Lamu region, which includes the popular tourist beach destination of Lamu Island, lies close to the Somali frontier and has suffered frequent attacks, often carried out with roadside bombs.
In mid-2014, close to 100 people were killed in a series of armed assaults on the inland town of Mpeketoni — in the same region as Monday’s attack — and surrounding villages in Lamu county.
Al-Shabaab fighters have staged several numerous attacks inside Kenya in retaliation for Nairobi sending troops into Somalia in 2011 as part of an African Union force to oust the jihadists.
In January 2020, the Islamists stormed a US military base in Lamu, destroying several aircraft and killing three Americans.
A year earlier, Al-Shabaab gunmen killed 21 people at an upscale hotel complex in Nairobi while previous attacks saw 67 killed at the Westgate shopping centre in 2013 and 148 at Garissa University in 2015.
The jihadists are seeking to overthrow the internationally-backed government in Mogadishu, and control swathes of southern Somalia from where they regularly launch attacks in the capital and elsewhere.
Somalia is gripped by political crisis with its president and prime minister locked in a feud over the country’s long-delayed elections, an impasse analysts say is distracting from the fight against the Al-Shabaab.