Kenyan police said Tuesday they had made eight arrests following a brutal attack in a coastal region bordering Somalia that left six people dead and homes in ashes.

One man was beheaded and five were shot or burned to death in the assault on a village in Lamu County which began late Sunday.

The Indian Ocean region has suffered violent incursions by Al-Shabaab and local authorities initially suspected the Somalia-based Islamist militants were behind the attack, although they did not rule out other motives.

There has not yet been any claim of responsibility and police said investigations so far suggested a land dispute could be at play.

Police issued a statement naming eight people who had been arrested over the killings.

"The investigation is progressing on well," National Police spokesman Bruno Shioso told AFP earlier, when he announced an initial four arrests.

"So far it has been established that the attack is linked to local disputes on land," he said, adding that such incidents were not uncommon in the area.

He said police were investigating whether a separate killing on Monday about 60 kilometres (35 miles) away was connected.

Police said the assailants in the earlier attack 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 a police report seen by AFP.

Several houses were also found torched and bullet casings recovered, the report said.

Lamu, which includes the popular tourist beach destination of Lamu Island, lies close to the Somali frontier and Al-Shabaab has staged cross-border attacks in the coastal region.

In January 2020, the Al-Qaeda-linked militants stormed a US military base in Lamu, destroying several aircraft and killing three Americans.

Al-Shabaab have targeted Kenya in retaliation for Nairobi sending troops into Somalia in 2011 as part of an African Union force to oust the jihadists.